diff --git a/builtin-functions/kphp-light/functions.txt b/builtin-functions/kphp-light/functions.txt
index 1a0d360a82..e06ff06ba3 100644
--- a/builtin-functions/kphp-light/functions.txt
+++ b/builtin-functions/kphp-light/functions.txt
@@ -11,6 +11,9 @@ define('PHP_INT_MIN', -9223372036854775808);
 define('PHP_INT_SIZE', 8);
 define('PHP_EOL', "\n");
 
+if (0) {
+  define('PHP_SAPI', php_sapi_name());//"Defined in source code"
+}
 
 /** @var mixed $_SERVER */
 global $_SERVER;
@@ -36,10 +39,16 @@ function intval ($v ::: mixed) ::: int;
 function floatval ($v ::: mixed) ::: float;
 function strval ($v ::: mixed) ::: string;
 
-/** @kphp-extern-func-info interruptible */
+/**
+ * @kphp-no-return
+ * @kphp-extern-func-info interruptible
+ */
 function exit($code = 0) ::: void;
 
-/** @kphp-extern-func-info interruptible */
+/**
+ * @kphp-no-return
+ * @kphp-extern-func-info interruptible
+ */
 function die($code = 0) ::: void;
 
 function ob_clean() ::: void;
diff --git a/builtin-functions/kphp-light/unsupported-functions.txt b/builtin-functions/kphp-light/unsupported-functions.txt
index bc71685454..3328705451 100644
--- a/builtin-functions/kphp-light/unsupported-functions.txt
+++ b/builtin-functions/kphp-light/unsupported-functions.txt
@@ -12,11 +12,13 @@ require_once __DIR__ . '/unsupported/kphp-toggles.txt';
 require_once __DIR__ . '/unsupported/kphp-tracing.txt';
 require_once __DIR__ . '/unsupported/kphp_internal.txt';
 require_once __DIR__ . '/unsupported/math.txt';
+require_once __DIR__ . '/unsupported/memcache.txt';
 require_once __DIR__ . '/unsupported/misc.txt';
 require_once __DIR__ . '/unsupported/regex.txt';
 require_once __DIR__ . '/unsupported/rpc.txt';
 require_once __DIR__ . '/unsupported/serialize.txt';
 require_once __DIR__ . '/unsupported/server.txt';
+require_once __DIR__ . '/unsupported/spl.txt';
 require_once __DIR__ . '/unsupported/string.txt';
 require_once __DIR__ . '/unsupported/time.txt';
 require_once __DIR__ . '/unsupported/uberh3.txt';
diff --git a/builtin-functions/kphp-light/unsupported/crypto.txt b/builtin-functions/kphp-light/unsupported/crypto.txt
index 6c8c0becc1..bc495881e8 100644
--- a/builtin-functions/kphp-light/unsupported/crypto.txt
+++ b/builtin-functions/kphp-light/unsupported/crypto.txt
@@ -26,6 +26,16 @@ define('OPENSSL_RAW_DATA', 1);
 define('OPENSSL_ZERO_PADDING', 2);
 define('OPENSSL_DONT_ZERO_PAD_KEY', 4);
 
+define('PKCS7_TEXT', 0x1);
+define('PKCS7_NOCERTS', 0x2);
+define('PKCS7_NOSIGS', 0x4);
+define('PKCS7_NOCHAIN', 0x8);
+define('PKCS7_NOINTERN', 0x10);
+define('PKCS7_NOVERIFY', 0x20);
+define('PKCS7_BINARY', 0x80);
+define('PKCS7_DETACHED', 0x40);
+define('PKCS7_NOATTR', 0x100);
+
 /** @kphp-extern-func-info generate-stub */
 function openssl_public_encrypt ($data ::: string, &$result ::: mixed, $key ::: string) ::: bool;
 /** @kphp-extern-func-info generate-stub */
diff --git a/builtin-functions/kphp-light/unsupported/file.txt b/builtin-functions/kphp-light/unsupported/file.txt
index 4d7db32feb..fc5017da9d 100644
--- a/builtin-functions/kphp-light/unsupported/file.txt
+++ b/builtin-functions/kphp-light/unsupported/file.txt
@@ -45,7 +45,7 @@ function unlink ($name ::: string) ::: bool;
 
 
  /** @kphp-extern-func-info generate-stub */
-function fgetcsv ($stream, $length = 0, $delimiter = ",", $enclosure = "\"", $escape = "\\") ::: mixed[] | false;
+function fgetcsv ($stream ::: mixed, $length ::: int = 0, $delimiter ::: string = ",", $enclosure ::: string = "\"", $escape ::: string = "\\") ::: mixed[] | false;
 
 define('STDIN', 'php://stdin');
 define('STDOUT', 'php://stdout');
@@ -59,29 +59,35 @@ define('SEEK_CUR', 2);
  /** @kphp-extern-func-info generate-stub */
 function fopen ($filename ::: string, $mode ::: string) ::: mixed;
  /** @kphp-extern-func-info generate-stub */
-function fwrite ($stream, $text ::: string) ::: int | false;
+function fwrite ($stream ::: mixed, $text ::: string) ::: int | false;
  /** @kphp-extern-func-info generate-stub */
-function fseek ($stream, $offset ::: int, $whence ::: int = SEEK_SET) ::: int;
+function fseek ($stream ::: mixed, $offset ::: int, $whence ::: int = SEEK_SET) ::: int;
  /** @kphp-extern-func-info generate-stub */
-function rewind ($stream) ::: bool;
+function rewind ($stream ::: mixed) ::: bool;
  /** @kphp-extern-func-info generate-stub */
-function ftell ($stream) ::: int | false;
+function ftell ($stream ::: mixed) ::: int | false;
  /** @kphp-extern-func-info generate-stub */
-function fread ($stream, $length ::: int) ::: string | false;
+function fread ($stream ::: mixed, $length ::: int) ::: string | false;
  /** @kphp-extern-func-info generate-stub */
-function fgetc ($stream) ::: string | false;
+function fgetc ($stream ::: mixed) ::: string | false;
  /** @kphp-extern-func-info generate-stub */
-function fpassthru ($stream) ::: int | false;
+function fpassthru ($stream ::: mixed) ::: int | false;
  /** @kphp-extern-func-info generate-stub */
-function fgets ($stream, $length ::: int = -1) ::: string | false;
+function fgets ($stream ::: mixed, $length ::: int = -1) ::: string | false;
  /** @kphp-extern-func-info generate-stub */
-function fflush ($stream) ::: bool;
+function fflush ($stream ::: mixed) ::: bool;
  /** @kphp-extern-func-info generate-stub */
-function feof ($stream) ::: bool;
+function feof ($stream ::: mixed) ::: bool;
  /** @kphp-extern-func-info generate-stub */
-function fclose ($stream) ::: bool;
+function fclose ($stream ::: mixed) ::: bool;
 
+define('STREAM_CLIENT_CONNECT', 1);
+define('DEFAULT_SOCKET_TIMEOUT', 60);
 
+/** @kphp-extern-func-info generate-stub */
+function stream_context_create ($options ::: mixed = array()) ::: mixed;
+
+function stream_socket_client ($url ::: string, &$error_number ::: mixed = TODO, &$error_description ::: mixed = TODO, $timeout ::: float = DEFAULT_SOCKET_TIMEOUT, $flags ::: int = STREAM_CLIENT_CONNECT, $context ::: mixed = null) ::: mixed;
 
 function fprintf ($stream, $format ::: string, ...$args) ::: int;
 function fputcsv ($stream, $fields ::: array, $delimiter = ",", $enclosure = "\"", $escape = "\\") ::: int | false;
diff --git a/builtin-functions/kphp-light/unsupported/fork.txt b/builtin-functions/kphp-light/unsupported/fork.txt
index 5b2c576b4a..71edd7bd79 100644
--- a/builtin-functions/kphp-light/unsupported/fork.txt
+++ b/builtin-functions/kphp-light/unsupported/fork.txt
@@ -6,11 +6,11 @@ function wait_concurrently ($id ::: future<any>) ::: bool;
 /** @kphp-extern-func-info can_throw generate-stub cpp_template_call */
 function wait_multi (future<any>[] $resumables) ::: (^1[*][*] | null)[];
 
-/** @kphp-extern-func-info generate-stub */
+
 function wait_queue_create (array< future<any> | false > $request_ids = []) ::: future_queue<^1[*][*]>;
-/** @kphp-extern-func-info generate-stub */
+
 function wait_queue_push (future_queue<any> &$queue_id, future<any> | false $request_ids) ::: void;
-/** @kphp-extern-func-info generate-stub */
+
 function wait_queue_empty (future_queue<any> $queue_id) ::: bool;
-/** @kphp-extern-func-info generate-stub */
+
 function wait_queue_next (future_queue<any> $queue_id, $timeout ::: float = -1.0) ::: future<^1[*]> | false;
diff --git a/builtin-functions/kphp-light/unsupported/hash.txt b/builtin-functions/kphp-light/unsupported/hash.txt
index 26ec14bebf..0e67b84a1d 100644
--- a/builtin-functions/kphp-light/unsupported/hash.txt
+++ b/builtin-functions/kphp-light/unsupported/hash.txt
@@ -30,10 +30,32 @@ function md5_file ($s ::: string, $raw_output ::: bool = false) ::: string | fal
 function sha1 ($s ::: string, $raw_output ::: bool = false) ::: string;
 
 
+define('ZLIB_ENCODING_RAW', -0x0f);
+define('ZLIB_ENCODING_DEFLATE', 0x0f);
+define('ZLIB_ENCODING_GZIP', 0x1f);
+
+define('ZLIB_NO_FLUSH', 0);
+define('ZLIB_PARTIAL_FLUSH', 1);
 define('ZLIB_SYNC_FLUSH', 2);
+define('ZLIB_FULL_FLUSH', 3);
+define('ZLIB_FINISH', 4);
+define('ZLIB_BLOCK', 5);
+define('ZLIB_TREES', 6);
+
+define('ZLIB_FILTERED', 1);
+define('ZLIB_HUFFMAN_ONLY', 2);
+define('ZLIB_RLE', 3);
+define('ZLIB_FIXED', 4);
+define('ZLIB_DEFAULT_STRATEGY', 0);
+
+/** @kphp-generate-stub-class */
+final class DeflateContext {
+    private function __construct() ::: DeflateContext;
+}
 
+// todo: deflate_init php signature has type array instead mixed
 /** @kphp-extern-func-info generate-stub */
-function deflate_init(int $encoding, array $options = []) ::: ?DeflateContext;
+function deflate_init(int $encoding, mixed $options = []) ::: ?DeflateContext;
 /** @kphp-extern-func-info generate-stub */
 function deflate_add(DeflateContext $context, string $data, int $flush_mode = ZLIB_SYNC_FLUSH) ::: string | false;
 /** @kphp-extern-func-info generate-stub */
diff --git a/builtin-functions/kphp-light/unsupported/kphp_internal.txt b/builtin-functions/kphp-light/unsupported/kphp_internal.txt
index ab53b80817..7700a372d3 100644
--- a/builtin-functions/kphp-light/unsupported/kphp_internal.txt
+++ b/builtin-functions/kphp-light/unsupported/kphp_internal.txt
@@ -4,6 +4,29 @@
 
 function _exception_set_location($e, string $filename, int $line): ^1;
 
+// microtime(false) specialization
+/** @kphp-extern-func-info generate-stub */
+function _microtime_string(): string;
+// microtime(true) specialization
+/** @kphp-extern-func-info generate-stub */
+function _microtime_float(): float;
+
+// hrtime(true) specialization
+/** @kphp-extern-func-info generate-stub */
+function _hrtime_int(): int;
+// hrtime(false) specialization
+/** @kphp-extern-func-info generate-stub */
+function _hrtime_array(): int[];
+
+// `new $c(...)` => `_by_name_construct($c, ...)`
+function _by_name_construct(string $class_name, ...$args) ::: instance<^1>;
+// `$c::method()` => `_by_name_call_method($c, 'method')`
+function _by_name_call_method(string $class_name, string $method_name, ...$args);
+// `$c::CONST` => `_by_name_get_const($c, 'CONST')`
+function _by_name_get_const(string $class_name, string $constant);
+// `$c::$field` => `_by_name_get_field($c, 'field')`
+function _by_name_get_field(string $class_name, string $field);
+
 
 /**
  * @kphp-extern-func-info generate-stub
diff --git a/builtin-functions/kphp-light/unsupported/memcache.txt b/builtin-functions/kphp-light/unsupported/memcache.txt
new file mode 100644
index 0000000000..40140ffe17
--- /dev/null
+++ b/builtin-functions/kphp-light/unsupported/memcache.txt
@@ -0,0 +1,46 @@
+<?php
+
+/** @kphp-generate-stub-class */
+interface Memcache {
+    public function get (string|string[] $key) ::: mixed;
+    public function delete (string $key) ::: bool;
+    public function add (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    public function set (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    public function replace (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    public function decrement (string $key, int $v = 1) ::: mixed;
+    public function increment (string $key, int $v = 1) ::: mixed;
+    public function getVersion () ::: mixed;
+
+    // this two functions shouldn't be there, but we need it to rewrite code
+    public function addServer (string $host, int $port = 11211, bool $persistent = true, int $weight = 1, float $timeout = 1, int $retry_interval = 15, bool $status = true, mixed $failure_callback = null, int $timeoutms = 0) ::: bool;
+    public function rpc_connect (string $host, int $port, mixed $default_actor_id = 0, float $timeout = 0.3, float $connect_timeout = 0.3, float $reconnect_timeout = 17.0) ::: bool;
+}
+
+
+/** @kphp-generate-stub-class */
+final class McMemcache implements Memcache {
+    /** @kphp-extern-func-info generate-stub */
+    public function __construct() ::: McMemcache;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function get (string|string[] $key) ::: mixed;
+    /** @kphp-extern-func-info generate-stub */
+    public function delete (string $key) ::: bool;
+    /** @kphp-extern-func-info generate-stub */
+    public function add (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    /** @kphp-extern-func-info generate-stub */
+    public function set (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    /** @kphp-extern-func-info generate-stub */
+    public function replace (string $key, mixed $value, int $flags = 0, int $expire = 0) ::: bool;
+    /** @kphp-extern-func-info generate-stub */
+    public function decrement (string $key, int $v = 1) ::: mixed;
+    /** @kphp-extern-func-info generate-stub */
+    public function increment (string $key, int $v = 1) ::: mixed;
+    /** @kphp-extern-func-info generate-stub */
+    public function getVersion () ::: mixed;
+    /** @kphp-extern-func-info generate-stub */
+    public function addServer (string $host, int $port = 11211, bool $persistent = true, int $weight = 1, float $timeout = 1, int $retry_interval = 15, bool $status = true, mixed $failure_callback = null, int $timeoutms = 0) ::: bool;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function rpc_connect (string $host, int $port, mixed $default_actor_id = 0, float $timeout = 0.3, float $connect_timeout = 0.3, float $reconnect_timeout = 17.0) ::: bool;
+}
\ No newline at end of file
diff --git a/builtin-functions/kphp-light/unsupported/misc.txt b/builtin-functions/kphp-light/unsupported/misc.txt
index 07aed62d95..db483bbddd 100644
--- a/builtin-functions/kphp-light/unsupported/misc.txt
+++ b/builtin-functions/kphp-light/unsupported/misc.txt
@@ -36,7 +36,7 @@ function htmlspecialchars_decode ($str ::: string, $flags ::: int = ENT_COMPAT)
 /** @kphp-extern-func-info generate-stub */
 function nl2br ($str ::: string, $is_xhtml ::: bool = true) ::: string;
 /** @kphp-extern-func-info generate-stub */
-function number_format ($number ::: float, $decimals ::: int = 0, $dec_point = '.', $thousands_sep = ',') ::: string;
+function number_format ($number ::: float, $decimals ::: int = 0, $dec_point ::: string = '.', $thousands_sep ::: string = ',') ::: string;
 /** @kphp-extern-func-info generate-stub */
 function ord ($c ::: string) ::: int;
 
diff --git a/builtin-functions/kphp-light/unsupported/rpc.txt b/builtin-functions/kphp-light/unsupported/rpc.txt
index fe40759e2e..3b8274731a 100644
--- a/builtin-functions/kphp-light/unsupported/rpc.txt
+++ b/builtin-functions/kphp-light/unsupported/rpc.txt
@@ -65,4 +65,8 @@ function new_rpc_connection ($str ::: string, $port ::: int, $actor_id ::: mixed
  /** @kphp-extern-func-info generate-stub */
 function extract_kphp_rpc_response_extra_info ($resumable_id ::: int) ::: ?tuple(int, float);
 
-
+/** @kphp-generate-stub-class */
+final class RpcConnection {
+    /** @kphp-extern-func-info generate-stub */
+    private function __construct();
+}
diff --git a/builtin-functions/kphp-light/unsupported/server.txt b/builtin-functions/kphp-light/unsupported/server.txt
index ea7127b595..02d79a39b8 100644
--- a/builtin-functions/kphp-light/unsupported/server.txt
+++ b/builtin-functions/kphp-light/unsupported/server.txt
@@ -82,6 +82,14 @@ function getopt ($options ::: string, $longopt ::: array = array(), ?int &$rest_
 /** @kphp-extern-func-info generate-stub */
 function profiler_set_function_label($label ::: string) ::: void;
 
+define('LC_ALL', 6);
+define('LC_COLLATE', 3);
+define('LC_CTYPE', 0);
+define('LC_MONETARY', 4);
+define('LC_NUMERIC', 1);
+define('LC_TIME', 2);
+define('LC_MESSAGES', 5);
+
 /** @kphp-extern-func-info generate-stub */
 function setlocale ($category ::: int, $locale ::: string) ::: string | false;
 
diff --git a/builtin-functions/kphp-light/unsupported/spl.txt b/builtin-functions/kphp-light/unsupported/spl.txt
new file mode 100644
index 0000000000..8ae0ac5af2
--- /dev/null
+++ b/builtin-functions/kphp-light/unsupported/spl.txt
@@ -0,0 +1,75 @@
+<?php
+
+/** @kphp-generate-stub-class */
+class ArithmeticError extends Error {}
+/** @kphp-generate-stub-class */
+class DivisionByZeroError extends ArithmeticError {}
+/** @kphp-generate-stub-class */
+class AssertionError extends Error {}
+/** @kphp-generate-stub-class */
+class CompileError extends Error {}
+/** @kphp-generate-stub-class */
+class ParseError extends CompileError {}
+/** @kphp-generate-stub-class */
+class TypeError extends Error {}
+/** @kphp-generate-stub-class */
+class ArgumentCountError extends TypeError {}
+/** @kphp-generate-stub-class */
+class ValueError extends Error {}
+/** @kphp-generate-stub-class */
+class UnhandledMatchError extends Error {}
+
+/** @kphp-generate-stub-class */
+class LogicException extends Exception {}
+/** @kphp-generate-stub-class */
+class BadFunctionCallException extends LogicException {}
+/** @kphp-generate-stub-class */
+class BadMethodCallException extends BadFunctionCallException {}
+/** @kphp-generate-stub-class */
+class DomainException extends LogicException {}
+/** @kphp-generate-stub-class */
+class InvalidArgumentException extends LogicException {}
+/** @kphp-generate-stub-class */
+class LengthException extends LogicException {}
+/** @kphp-generate-stub-class */
+class OutOfRangeException extends LogicException {}
+
+/** @kphp-generate-stub-class */
+class RuntimeException extends Exception {}
+/** @kphp-generate-stub-class */
+class OutOfBoundsException extends RuntimeException {}
+/** @kphp-generate-stub-class */
+class OverflowException extends RuntimeException {}
+/** @kphp-generate-stub-class */
+class RangeException extends RuntimeException {}
+/** @kphp-generate-stub-class */
+class UnderflowException extends RuntimeException {}
+/** @kphp-generate-stub-class */
+class UnexpectedValueException extends RuntimeException {}
+
+/** @kphp-generate-stub-class */
+class Random\RandomException extends Exception {}
+
+// https://www.php.net/manual/en/class.arrayiterator.php
+// TODO: make it work with T[] arrays when generic classes are available.
+// For now, it only supports mixed[].
+/** @kphp-generate-stub-class */
+final class ArrayIterator {
+    /** @kphp-extern-func-info generate-stub */
+    public function __construct($arr ::: mixed[]);
+
+    /** @kphp-extern-func-info generate-stub */
+    public function count(): int;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function current(): mixed;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function key(): mixed;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function next(): void;
+
+    /** @kphp-extern-func-info generate-stub */
+    public function valid(): bool;
+}
diff --git a/builtin-functions/kphp-light/unsupported/string.txt b/builtin-functions/kphp-light/unsupported/string.txt
index e013b803b8..0a689517c2 100644
--- a/builtin-functions/kphp-light/unsupported/string.txt
+++ b/builtin-functions/kphp-light/unsupported/string.txt
@@ -31,12 +31,11 @@ function str_starts_with ($haystack ::: string, $needle ::: string) ::: bool;
 /** @kphp-extern-func-info generate-stub */
 function str_ends_with ($haystack ::: string, $needle ::: string) ::: bool;
 
-
-/** @kphp-extern-func-info generate-stub */
-function strtr ($subject ::: string, $replace_pairs, $third = TODO) ::: string;//TODO
 /** @kphp-extern-func-info generate-stub */
+function strtr ($subject ::: string, $replace_pairs ::: mixed, $third ::: mixed = TODO) ::: string;//TODO
+
 function str_replace ($search, $replace, $subject, &$count ::: int = TODO) ::: ^3 | string;
-/** @kphp-extern-func-info generate-stub */
+
 function str_ireplace ($search, $replace, $subject, &$count ::: int = TODO) ::: ^3 | string;
 /** @kphp-extern-func-info generate-stub */
 function str_split ($str ::: string, $split_length ::: int = 1) ::: string[];
@@ -52,6 +51,7 @@ function strripos ($haystack ::: string, $needle ::: string, $offset ::: int = 0
 function strstr ($haystack ::: string, $needle ::: string, $before_needle ::: bool = false) ::: string | false;
 /** @kphp-extern-func-info generate-stub */
 function stristr ($haystack ::: string, $needle ::: string, $before_needle ::: bool = false) ::: string | false;
+/** @kphp-extern-func-info generate-stub */
 function strrchr ($haystack ::: string, $needle ::: string) ::: string | false;
 /** @kphp-extern-func-info generate-stub */
 function strrev ($str ::: string) ::: string;
@@ -95,7 +95,7 @@ function ltrim ($s ::: string, $what ::: string = " \n\r\t\v\0") ::: string;
 /** @kphp-extern-func-info generate-stub */
 function rtrim ($s ::: string, $what ::: string = " \n\r\t\v\0") ::: string;
 
-/** @kphp-extern-func-info generate-stub */
+
 function similar_text ($first ::: string, $second ::: string, float &$percent = TODO) ::: int;
 
 
@@ -141,16 +141,6 @@ function zstd_compress(string $data, int $level = 3) ::: string | false;
 /** @kphp-extern-func-info generate-stub */
 function zstd_uncompress(string $data) ::: string | false;
 
-
-define('STREAM_CLIENT_CONNECT', 1);
-define('DEFAULT_SOCKET_TIMEOUT', 60);
-
-/** @kphp-extern-func-info generate-stub */
-function stream_context_create ($options ::: mixed = array()) ::: mixed;
-/** @kphp-extern-func-info generate-stub */
-function stream_socket_client ($url ::: string, &$error_number ::: mixed = TODO, &$error_description ::: mixed = TODO, $timeout ::: float = DEFAULT_SOCKET_TIMEOUT, $flags ::: int = STREAM_CLIENT_CONNECT, $context = null) ::: mixed;
-
-
 /** @kphp-extern-func-info generate-stub */
 function getimagesize ($name ::: string) ::: mixed;
 
diff --git a/compiler/code-gen/declarations.cpp b/compiler/code-gen/declarations.cpp
index f1fe0c5318..33612333b2 100644
--- a/compiler/code-gen/declarations.cpp
+++ b/compiler/code-gen/declarations.cpp
@@ -949,6 +949,10 @@ void ClassDeclaration::compile_accept_visitor_methods(CodeGenerator &W, ClassPtr
 }
 
 void ClassDeclaration::compile_msgpack_declarations(CodeGenerator &W, ClassPtr klass) {
+  if (G->is_output_mode_k2()) {
+    // The current version of runtime-light does not support visitors
+    return;
+  }
   if (!klass->is_serializable) {
     return;
   }
diff --git a/compiler/code-gen/files/function-header.cpp b/compiler/code-gen/files/function-header.cpp
index 8a17edc921..f75890d0e4 100644
--- a/compiler/code-gen/files/function-header.cpp
+++ b/compiler/code-gen/files/function-header.cpp
@@ -37,9 +37,6 @@ void FunctionH::compile(CodeGenerator &W) const {
     W << "inline ";
   }
   W << FunctionDeclaration(function, true);
-  if (function->is_no_return) {
-    W << " __attribute__((noreturn))";
-  }
   if (function->is_flatten) {
     W << " __attribute__((flatten))";
   }
diff --git a/compiler/code-gen/files/function-source.cpp b/compiler/code-gen/files/function-source.cpp
index a5afbcd157..d464e457fc 100644
--- a/compiler/code-gen/files/function-source.cpp
+++ b/compiler/code-gen/files/function-source.cpp
@@ -41,6 +41,9 @@ void FunctionCpp::compile(CodeGenerator &W) const {
   W << includes;
 
   W << OpenNamespace();
+  if (function->is_no_return) {
+    W << "[[noreturn]] ";
+  }
   declare_const_vars(function, W);
 
   W << UnlockComments();
diff --git a/compiler/code-gen/vertex-compiler.cpp b/compiler/code-gen/vertex-compiler.cpp
index 16b2210ae7..2a2b56c60a 100644
--- a/compiler/code-gen/vertex-compiler.cpp
+++ b/compiler/code-gen/vertex-compiler.cpp
@@ -291,6 +291,10 @@ void compile_noerr(VertexAdaptor<op_noerr> root, CodeGenerator &W) {
 }
 
 void compile_throw(VertexAdaptor<op_throw> root, CodeGenerator &W) {
+  if (G->is_output_mode_k2()) {
+    // The current version of runtime-light does not support exception throw
+    return;
+  }
   W << BEGIN <<
     "THROW_EXCEPTION " << MacroBegin{} << root->exception() << MacroEnd{} << ";" << NL <<
     ThrowAction() << ";" << NL <<
@@ -298,6 +302,10 @@ void compile_throw(VertexAdaptor<op_throw> root, CodeGenerator &W) {
 }
 
 void compile_try(VertexAdaptor<op_try> root, CodeGenerator &W) {
+  if (G->is_output_mode_k2()) {
+    // The current version of runtime-light does not support try blocks
+    return;
+  }
   auto move_exception = [&](ClassPtr caught_class, VertexAdaptor<op_var> dst) {
     if (caught_class->name == "Throwable") {
       W << dst << " = std::move(CurException);" << NL;
diff --git a/compiler/pipes/parse-and-apply-phpdoc.cpp b/compiler/pipes/parse-and-apply-phpdoc.cpp
index 559bda7096..aa2dc9cc4c 100644
--- a/compiler/pipes/parse-and-apply-phpdoc.cpp
+++ b/compiler/pipes/parse-and-apply-phpdoc.cpp
@@ -266,7 +266,8 @@ class ParseAndApplyPhpDocForFunction {
       }
 
       case PhpDocType::kphp_extern_func_info: {
-        kphp_error(f_->is_extern(), "@kphp-extern-func-info used for regular function");
+        // This is temporary solution for generate-stub
+        bool doc_is_generated_stub = false;
         std::istringstream is(tag.value_as_string());
         std::string token;
         while (is >> token) {
@@ -285,10 +286,12 @@ class ParseAndApplyPhpDocForFunction {
             f_->is_interruptible = true;
           } else if (token == "generate-stub") {
             f_->need_generated_stub = true;
+            doc_is_generated_stub = true;
           } else {
             kphp_error(0, fmt_format("Unknown @kphp-extern-func-info {}", token));
           }
         }
+        kphp_error(f_->is_extern() || (f_->is_constructor() && doc_is_generated_stub), "@kphp-extern-func-info used for regular function");
         break;
       }
 
diff --git a/runtime/null_coalesce.h b/runtime-core/core-types/definition/null_coalesce.h
similarity index 100%
rename from runtime/null_coalesce.h
rename to runtime-core/core-types/definition/null_coalesce.h
diff --git a/runtime-light/component/component.h b/runtime-light/component/component.h
index 27cfb1cff3..83c88b3f30 100644
--- a/runtime-light/component/component.h
+++ b/runtime-light/component/component.h
@@ -16,12 +16,14 @@
 #include "runtime-light/coroutine/task.h"
 #include "runtime-light/header.h"
 #include "runtime-light/scheduler/scheduler.h"
+#include "runtime-light/stdlib/curl/curl-context.h"
+#include "runtime-light/stdlib/file/file-stream-context.h"
 #include "runtime-light/stdlib/fork/fork-context.h"
 #include "runtime-light/stdlib/job-worker/job-worker-context.h"
 #include "runtime-light/stdlib/output/output-buffer.h"
-#include "runtime-light/stdlib/regex/regex-functions.h"
-#include "runtime-light/stdlib/curl/curl.h"
+#include "runtime-light/stdlib/regex/regex-context.h"
 #include "runtime-light/stdlib/rpc/rpc-context.h"
+#include "runtime-light/stdlib/string/string-context.h"
 
 constexpr uint64_t INVALID_PLATFORM_DESCRIPTOR = 0;
 
@@ -102,8 +104,10 @@ struct ComponentState {
   JobWorkerClientComponentContext job_worker_client_component_context{};
   JobWorkerServerComponentContext job_worker_server_component_context{};
 
-  RegexComponentState regex_component_context;
-  CurlComponentState curl_component_state;
+  RegexComponentContext regex_component_context;
+  CurlComponentContext curl_component_context;
+  StringComponentContext string_component_context;
+  FileStreamComponentContext file_stream_component_context;
 
 private:
   task_t<void> main_task_;
diff --git a/runtime-light/stdlib/array/array-functions.h b/runtime-light/stdlib/array/array-functions.h
index 4eec86f6df..34f0edcc64 100644
--- a/runtime-light/stdlib/array/array-functions.h
+++ b/runtime-light/stdlib/array/array-functions.h
@@ -536,3 +536,18 @@ auto f$array_column(const Optional<T> &a, const mixed &column_key,
                     const mixed &index_key = {}) -> decltype(f$array_column(std::declval<T>(), column_key, index_key)) {
   php_critical_error("call to unsupported function");
 }
+
+template<class T>
+mixed f$array_key_first(const array<T> &a) {
+  php_critical_error("call to unsupported function");
+}
+
+template<class T>
+mixed f$array_key_last(const array<T> &a) {
+  php_critical_error("call to unsupported function");
+}
+
+template<class T, class T1>
+std::tuple<typename array<T>::key_type, T> f$array_find(const array<T> &a,  const T1 &callback) {
+  php_critical_error("call to unsupported function");
+}
diff --git a/runtime-light/stdlib/curl/curl.cpp b/runtime-light/stdlib/curl/curl-context.cpp
similarity index 57%
rename from runtime-light/stdlib/curl/curl.cpp
rename to runtime-light/stdlib/curl/curl-context.cpp
index d774c103e6..3e68fcb3e6 100644
--- a/runtime-light/stdlib/curl/curl.cpp
+++ b/runtime-light/stdlib/curl/curl-context.cpp
@@ -2,11 +2,11 @@
 // Copyright (c) 2024 LLC «V Kontakte»
 // Distributed under the GPL v3 License, see LICENSE.notice.txt
 
-#include "runtime-light/stdlib/curl/curl.h"
+#include "runtime-light/stdlib/curl/curl-context.h"
 
 #include "runtime-light/component/component.h"
 #include "runtime-light/utils/context.h"
 
-CurlComponentState &CurlComponentState::get() noexcept {
-  return get_component_context()->curl_component_state;
+CurlComponentContext &CurlComponentContext::get() noexcept {
+  return get_component_context()->curl_component_context;
 }
diff --git a/runtime-light/stdlib/curl/curl-context.h b/runtime-light/stdlib/curl/curl-context.h
new file mode 100644
index 0000000000..e6a13a208f
--- /dev/null
+++ b/runtime-light/stdlib/curl/curl-context.h
@@ -0,0 +1,13 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include <cstdint>
+
+struct CurlComponentContext {
+  int64_t curl_multi_info_read_msgs_in_queue_stub{};
+
+  static CurlComponentContext &get() noexcept;
+};
diff --git a/runtime-light/stdlib/curl/curl.h b/runtime-light/stdlib/curl/curl-functions.h
similarity index 70%
rename from runtime-light/stdlib/curl/curl.h
rename to runtime-light/stdlib/curl/curl-functions.h
index 6a4f91bb76..3618779984 100644
--- a/runtime-light/stdlib/curl/curl.h
+++ b/runtime-light/stdlib/curl/curl-functions.h
@@ -7,14 +7,9 @@
 #include <cstdint>
 
 #include "runtime-core/runtime-core.h"
+#include "runtime-light/stdlib/curl/curl-context.h"
 
-struct CurlComponentState {
-  int64_t curl_multi_info_read_msgs_in_queue_stub{};
-
-  static CurlComponentState &get() noexcept;
-};
-
-inline Optional<array<int64_t>> f$curl_multi_info_read(int64_t, int64_t & = CurlComponentState::get().curl_multi_info_read_msgs_in_queue_stub) {
+inline Optional<array<int64_t>> f$curl_multi_info_read(int64_t, int64_t & = CurlComponentContext::get().curl_multi_info_read_msgs_in_queue_stub) {
   php_critical_error("call to unsupported function : curl_multi_info_read");
 }
 
diff --git a/runtime-light/stdlib/exception/exception-functions.h b/runtime-light/stdlib/exception/exception-functions.h
index a45eb14837..3b93f85c62 100644
--- a/runtime-light/stdlib/exception/exception-functions.h
+++ b/runtime-light/stdlib/exception/exception-functions.h
@@ -7,7 +7,32 @@
 
 #include "runtime-core/runtime-core.h"
 
+#define THROW_EXCEPTION(e) {php_critical_error("Exceptions unsupported");}
+
+#define CHECK_EXCEPTION(action)
+
+#ifdef __clang__
+  #define TRY_CALL_RET_(x) x
+#else
+  #define TRY_CALL_RET_(x) std::move(x)
+#endif
+
+#define TRY_CALL_(CallT, call, action) ({ \
+CallT x_tmp___ = (call);                \
+CHECK_EXCEPTION(action);                \
+TRY_CALL_RET_(x_tmp___);                \
+})
+
+#define TRY_CALL_VOID_(call, action) ({(call); CHECK_EXCEPTION(action); void();})
+
+#define TRY_CALL(CallT, ResT, call) TRY_CALL_(CallT, call, return (ResT()))
+#define TRY_CALL_VOID(ResT, call) TRY_CALL_VOID_(call, return (ResT()))
+
+#define TRY_CALL_EXIT(CallT, message, call) TRY_CALL_(CallT, call, php_critical_error (message))
+#define TRY_CALL_VOID_EXIT(message, call) TRY_CALL_VOID_(call, php_critical_error (message))
+
+
 template<typename T>
 T f$_exception_set_location(const T &e, const string &file, int64_t line) {
-  php_critical_error("call to unsupported function : _exception_set_location");
+  php_critical_error("call to unsupported function");
 }
diff --git a/runtime-light/stdlib/file/file-stream-context.cpp b/runtime-light/stdlib/file/file-stream-context.cpp
new file mode 100644
index 0000000000..9edf534b8e
--- /dev/null
+++ b/runtime-light/stdlib/file/file-stream-context.cpp
@@ -0,0 +1,11 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#include "runtime-light/stdlib/file/file-stream-context.h"
+
+#include "runtime-light/component/component.h"
+
+FileStreamComponentContext &FileStreamComponentContext::get() noexcept {
+  return get_component_context()->file_stream_component_context;
+}
diff --git a/runtime-light/stdlib/file/file-stream-context.h b/runtime-light/stdlib/file/file-stream-context.h
new file mode 100644
index 0000000000..7648c61cae
--- /dev/null
+++ b/runtime-light/stdlib/file/file-stream-context.h
@@ -0,0 +1,14 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include "runtime-core/runtime-core.h"
+
+struct FileStreamComponentContext {
+  mixed error_number_dummy;
+  mixed error_description_dummy;
+
+  static FileStreamComponentContext &get() noexcept;
+};
diff --git a/runtime-light/stdlib/file/file-stream-functions.h b/runtime-light/stdlib/file/file-stream-functions.h
new file mode 100644
index 0000000000..43ef4f4cd9
--- /dev/null
+++ b/runtime-light/stdlib/file/file-stream-functions.h
@@ -0,0 +1,15 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include <cstdint>
+
+#include "runtime-light/stdlib/file/file-stream-context.h"
+
+inline mixed f$stream_socket_client(const string &, mixed & = FileStreamComponentContext::get().error_number_dummy,
+                                    mixed & = FileStreamComponentContext::get().error_description_dummy, double = -1, int64_t = 1,
+                                    const mixed & = mixed()) {
+  php_critical_error("call to unsupported function");
+}
diff --git a/runtime-light/stdlib/fork/fork-functions.h b/runtime-light/stdlib/fork/fork-functions.h
index 5e98a6d6cb..348b4471cc 100644
--- a/runtime-light/stdlib/fork/fork-functions.h
+++ b/runtime-light/stdlib/fork/fork-functions.h
@@ -27,7 +27,7 @@ inline constexpr auto DEFAULT_TIMEOUT_NS = std::chrono::duration_cast<std::chron
 // === Blocking API ================================================================================
 
 template<typename T>
-requires(is_optional<T>::value || std::same_as<T, mixed>) task_t<T> f$wait(int64_t fork_id, double timeout = -1.0) noexcept {
+requires(is_optional<T>::value || std::same_as<T, mixed> || is_class_instance<T>::value) task_t<T> f$wait(int64_t fork_id, double timeout = -1.0) noexcept {
   auto &fork_ctx{ForkComponentContext::get()};
   if (!fork_ctx.contains(fork_id)) {
     php_warning("can't find fork %" PRId64, fork_id);
@@ -42,7 +42,7 @@ requires(is_optional<T>::value || std::same_as<T, mixed>) task_t<T> f$wait(int64
 }
 
 template<typename T>
-requires(is_optional<T>::value || std::same_as<T, mixed>) task_t<T> f$wait(Optional<int64_t> fork_id_opt, double timeout = -1.0) noexcept {
+requires(is_optional<T>::value || std::same_as<T, mixed> || is_class_instance<T>::value) task_t<T> f$wait(Optional<int64_t> fork_id_opt, double timeout = -1.0) noexcept {
   co_return co_await f$wait<T>(fork_id_opt.has_value() ? fork_id_opt.val() : INVALID_FORK_ID, timeout);
 }
 
@@ -63,3 +63,23 @@ inline task_t<void> f$sched_yield_sleep(double duration) noexcept {
 inline int64_t f$get_running_fork_id() noexcept {
   return ForkComponentContext::get().running_fork_id;
 }
+
+inline int64_t f$wait_queue_create() {
+  php_critical_error("call to unsupported function");
+}
+
+inline int64_t f$wait_queue_create(const mixed &resumable_ids) {
+  php_critical_error("call to unsupported function");
+}
+
+inline int64_t f$wait_queue_push(int64_t queue_id, const mixed &resumable_ids) {
+  php_critical_error("call to unsupported function");
+}
+
+inline bool f$wait_queue_empty(int64_t queue_id) {
+  php_critical_error("call to unsupported function");
+}
+
+inline Optional<int64_t> f$wait_queue_next(int64_t queue_id, double timeout = -1.0) {
+  php_critical_error("call to unsupported function");
+}
diff --git a/runtime-light/stdlib/math/random-functions.h b/runtime-light/stdlib/math/random-functions.h
index bc14fb1cad..ba5dfa3ecb 100644
--- a/runtime-light/stdlib/math/random-functions.h
+++ b/runtime-light/stdlib/math/random-functions.h
@@ -5,6 +5,3 @@
 #include <cstdint>
 #include <random>
 
-inline int64_t f$rand() noexcept {
-  return static_cast<int64_t>(std::random_device{}());
-}
diff --git a/runtime-light/stdlib/output/http-functions.h b/runtime-light/stdlib/output/http-functions.h
new file mode 100644
index 0000000000..797204fbaa
--- /dev/null
+++ b/runtime-light/stdlib/output/http-functions.h
@@ -0,0 +1,14 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include <cstdint>
+
+#include "runtime-core/runtime-core.h"
+
+template<class T>
+string f$http_build_query(const array<T> &a, const string &numeric_prefix = {}, const string &arg_separator = string(), int64_t enc_type = 1) {
+  php_critical_error("call to unsupported function");
+}
diff --git a/runtime-light/stdlib/regex/regex-functions.cpp b/runtime-light/stdlib/regex/regex-context.cpp
similarity index 82%
rename from runtime-light/stdlib/regex/regex-functions.cpp
rename to runtime-light/stdlib/regex/regex-context.cpp
index 561d3493c5..ef73837c1e 100644
--- a/runtime-light/stdlib/regex/regex-functions.cpp
+++ b/runtime-light/stdlib/regex/regex-context.cpp
@@ -6,6 +6,6 @@
 
 #include "runtime-light/component/component.h"
 
-RegexComponentState &RegexComponentState::get() noexcept {
+RegexComponentContext &RegexComponentContext::get() noexcept {
   return get_component_context()->regex_component_context;
 }
diff --git a/runtime-light/stdlib/regex/regex-context.h b/runtime-light/stdlib/regex/regex-context.h
new file mode 100644
index 0000000000..3fb8d15303
--- /dev/null
+++ b/runtime-light/stdlib/regex/regex-context.h
@@ -0,0 +1,13 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include <cstdint>
+
+struct RegexComponentContext {
+  int64_t preg_replace_count_dummy{};
+
+  static RegexComponentContext &get() noexcept;
+};
diff --git a/runtime-light/stdlib/regex/regex-functions.h b/runtime-light/stdlib/regex/regex-functions.h
index 5c0c2e6369..7f28cf729c 100644
--- a/runtime-light/stdlib/regex/regex-functions.h
+++ b/runtime-light/stdlib/regex/regex-functions.h
@@ -5,12 +5,7 @@
 #pragma once
 
 #include "runtime-core/runtime-core.h"
-
-struct RegexComponentState {
-  int64_t preg_replace_count_dummy{};
-
-  static RegexComponentState &get() noexcept;
-};
+#include "runtime-light/stdlib/regex/regex-context.h"
 
 class regexp final : private vk::not_copyable {
 public:
@@ -25,83 +20,83 @@ class regexp final : private vk::not_copyable {
 
 template<class T1, class T2, class T3, class = enable_if_t_is_optional<T3>>
 auto f$preg_replace(const T1 &regex, const T2 &replace_val, const T3 &subject, int64_t limit = -1,
-                    int64_t &replace_count = RegexComponentState::get().preg_replace_count_dummy) {
+                    int64_t &replace_count = RegexComponentContext::get().preg_replace_count_dummy) {
   return f$preg_replace(regex, replace_val, subject.val(), limit, replace_count);
 }
 
 inline Optional<string> f$preg_replace(const regexp &, const string &, const string &, int64_t = -1,
-                                       int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                       int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 inline Optional<string> f$preg_replace(const regexp &, const mixed &, const string &, int64_t = -1,
-                                       int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                       int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline mixed f$preg_replace(const regexp &, const string &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+inline mixed f$preg_replace(const regexp &, const string &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline mixed f$preg_replace(const regexp &, const mixed &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+inline mixed f$preg_replace(const regexp &, const mixed &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 template<class T1, class T2>
 auto f$preg_replace(const string &regex, const T1 &replace_val, const T2 &subject, int64_t limit,
-                    int64_t &replace_count = RegexComponentState::get().preg_replace_count_dummy) {
+                    int64_t &replace_count = RegexComponentContext::get().preg_replace_count_dummy) {
   return f$preg_replace(regexp(regex), replace_val, subject, limit, replace_count);
 }
 
 inline Optional<string> f$preg_replace(const mixed &, const string &, const string &, int64_t = -1,
-                                       int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                       int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline mixed f$preg_replace(const mixed &, const string &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+inline mixed f$preg_replace(const mixed &, const string &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 inline Optional<string> f$preg_replace(const mixed &, const mixed &, const string &, int64_t = -1,
-                                       int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                       int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline mixed f$preg_replace(const mixed &, const mixed &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+inline mixed f$preg_replace(const mixed &, const mixed &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 template<class T1, class T2, class T3, class = enable_if_t_is_optional<T3>>
 auto f$preg_replace_callback(const T1 &regex, const T2 &replace_val, const T3 &subject, int64_t limit = -1,
-                             int64_t &replace_count = RegexComponentState::get().preg_replace_count_dummy) {
+                             int64_t &replace_count = RegexComponentContext::get().preg_replace_count_dummy) {
   return f$preg_replace_callback(regex, replace_val, subject.val(), limit, replace_count);
 }
 
 template<class T>
 Optional<string> f$preg_replace_callback(const regexp &, const T &, const string &, int64_t = -1,
-                                         int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                         int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 template<class T>
-mixed f$preg_replace_callback(const regexp &, const T &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+mixed f$preg_replace_callback(const regexp &, const T &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 template<class T, class T2>
 auto f$preg_replace_callback(const string &regex, const T &replace_val, const T2 &subject, int64_t limit = -1,
-                             int64_t &replace_count = RegexComponentState::get().preg_replace_count_dummy) {
+                             int64_t &replace_count = RegexComponentContext::get().preg_replace_count_dummy) {
   return f$preg_replace_callback(regexp(regex), replace_val, subject, limit, replace_count);
 }
 
 template<class T>
 Optional<string> f$preg_replace_callback(const mixed &, const T &, const string &, int64_t = -1,
-                                         int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+                                         int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
 template<class T>
-mixed f$preg_replace_callback(const mixed &, const T &, const mixed &, int64_t = -1, int64_t & = RegexComponentState::get().preg_replace_count_dummy) {
+mixed f$preg_replace_callback(const mixed &, const T &, const mixed &, int64_t = -1, int64_t & = RegexComponentContext::get().preg_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
diff --git a/runtime-light/stdlib/serialization/instance-serialize.h b/runtime-light/stdlib/serialization/instance-serialize.h
new file mode 100644
index 0000000000..ab54777838
--- /dev/null
+++ b/runtime-light/stdlib/serialization/instance-serialize.h
@@ -0,0 +1,29 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include "runtime-core/runtime-core.h"
+
+
+template<class InstanceClass>
+Optional<string> f$instance_serialize(const class_instance<InstanceClass> &instance) noexcept {
+  php_critical_error("call to unsupported function");
+}
+
+
+template<class InstanceClass>
+string f$instance_serialize_safe(const class_instance<InstanceClass> &instance) noexcept {
+  php_critical_error("call to unsupported function");
+}
+
+template<class ResultClass>
+ResultClass f$instance_deserialize(const string &buffer, const string&) noexcept {
+  php_critical_error("call to unsupported function");
+}
+
+template<class ResultClass>
+ResultClass f$instance_deserialize_safe(const string &buffer, const string&) noexcept {
+  php_critical_error("call to unsupported function");
+}
diff --git a/runtime-light/stdlib/stdlib.cmake b/runtime-light/stdlib/stdlib.cmake
index abefe33df5..3c0118261a 100644
--- a/runtime-light/stdlib/stdlib.cmake
+++ b/runtime-light/stdlib/stdlib.cmake
@@ -3,14 +3,14 @@ prepend(
   stdlib/
   component/component-api.cpp
   crypto/crypto-functions.cpp
-  curl/curl.cpp
+  curl/curl-context.cpp
   exit/exit-functions.cpp
   fork/fork-context.cpp
   job-worker/job-worker-api.cpp
   job-worker/job-worker-context.cpp
   output/output-buffer.cpp
   output/print-functions.cpp
-  regex/regex-functions.cpp
+  regex/regex-context.cpp
   rpc/rpc-api.cpp
   rpc/rpc-context.cpp
   rpc/rpc-extra-headers.cpp
@@ -18,4 +18,6 @@ prepend(
   rpc/rpc-tl-error.cpp
   rpc/rpc-tl-query.cpp
   rpc/rpc-tl-request.cpp
-  string/concat.cpp)
+  string/concat.cpp
+  string/string-context.cpp
+  file/file-stream-context.cpp)
diff --git a/runtime-light/stdlib/string/concat.h b/runtime-light/stdlib/string/concat.h
index 7f00179b56..6d0a2fbd41 100644
--- a/runtime-light/stdlib/string/concat.h
+++ b/runtime-light/stdlib/string/concat.h
@@ -6,16 +6,6 @@
 
 #include "runtime-core/runtime-core.h"
 
-template<class T>
-string f$strtr(const string &, const array<T> &) {
-  php_critical_error("call to unsupported function");
-}
-
-template<class T>
-Optional<int64_t> f$strpos(const string &, const Optional<T> &, int64_t = 0) {
-  php_critical_error("call to unsupported function");
-}
-
 // str_concat_arg generalizes both tmp_string and string arguments;
 // it can be constructed from both of them, so concat functions can operate
 // on both tmp_string and string types
diff --git a/runtime-light/stdlib/string/string-context.cpp b/runtime-light/stdlib/string/string-context.cpp
new file mode 100644
index 0000000000..1509af2676
--- /dev/null
+++ b/runtime-light/stdlib/string/string-context.cpp
@@ -0,0 +1,11 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#include "runtime-light/stdlib/string/string-context.h"
+
+#include "runtime-light/component/component.h"
+
+StringComponentContext &StringComponentContext::get() noexcept {
+  return get_component_context()->string_component_context;
+}
diff --git a/runtime-light/stdlib/string/string-context.h b/runtime-light/stdlib/string/string-context.h
new file mode 100644
index 0000000000..3ebe9ef171
--- /dev/null
+++ b/runtime-light/stdlib/string/string-context.h
@@ -0,0 +1,16 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2024 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include <cstdint>
+
+#include "runtime-core/runtime-core.h"
+
+struct StringComponentContext {
+  int64_t str_replace_count_dummy{};
+  double default_similar_text_percent_stub{};
+
+  static StringComponentContext &get() noexcept;
+};
diff --git a/runtime-light/stdlib/string/string-functions.h b/runtime-light/stdlib/string/string-functions.h
index 7063a939e9..da0e045ffb 100644
--- a/runtime-light/stdlib/string/string-functions.h
+++ b/runtime-light/stdlib/string/string-functions.h
@@ -2,51 +2,107 @@
 // Copyright (c) 2024 LLC «V Kontakte»
 // Distributed under the GPL v3 License, see LICENSE.notice.txt
 
+#pragma once
+
 #include <cstdint>
 
-#include "runtime-core/runtime-core.h"
+#include "runtime-light/stdlib/string/string-context.h"
+
+template<class T>
+Optional<int64_t> f$strpos(const string &, const Optional<T> &, int64_t = 0) {
+  php_critical_error("call to unsupported function");
+}
 
 inline int64_t f$strlen(const string &s) noexcept {
   return s.size();
 }
 
-inline tmp_string f$_tmp_substr(const string &str, int64_t start, int64_t length = std::numeric_limits<int64_t>::max()) {
+inline tmp_string f$_tmp_substr(const string &, int64_t, int64_t = std::numeric_limits<int64_t>::max()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline tmp_string f$_tmp_substr(tmp_string, int64_t, int64_t = std::numeric_limits<int64_t>::max()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline tmp_string f$_tmp_trim(tmp_string, const string & = string()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline tmp_string f$_tmp_trim(const string &, const string & = string()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline string f$trim(tmp_string, const string & = string()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline string f$trim(const string &, const string & = string()) {
+  php_critical_error("call to unsupported function");
+}
+
+inline Optional<string> f$substr(const string &, int64_t, int64_t = std::numeric_limits<int64_t>::max()) {
   php_critical_error("call to unsupported function");
 }
 
-inline tmp_string f$_tmp_substr(tmp_string str, int64_t start, int64_t length = std::numeric_limits<int64_t>::max()) {
+inline Optional<string> f$substr(tmp_string, int64_t, int64_t = std::numeric_limits<int64_t>::max()) {
   php_critical_error("call to unsupported function");
 }
 
-inline tmp_string f$_tmp_trim(tmp_string s, const string &what = string()) {
+inline string f$pack(const string &, const array<mixed> &) {
   php_critical_error("call to unsupported function");
 }
 
-inline tmp_string f$_tmp_trim(const string &s, const string &what = string()) {
+inline Optional<array<mixed>> f$unpack(const string &, const string &) {
   php_critical_error("call to unsupported function");
 }
 
-inline string f$trim(tmp_string s, const string &what = string()) {
+inline mixed f$str_replace(const mixed &, const mixed &, const mixed &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline string f$trim(const string &s, const string &what = string()) {
+inline string f$str_replace(const string &, const string &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline Optional<string> f$substr(const string &str, int64_t start, int64_t length = std::numeric_limits<int64_t>::max()) {
+template<typename T1, typename T2>
+string f$str_replace(const array<T1> &, const array<T2> &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline Optional<string> f$substr(tmp_string, int64_t start, int64_t length = std::numeric_limits<int64_t>::max()) {
+inline string f$str_replace(const mixed &, const mixed &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
+template<class T1, class T2, class SubjectT, class = enable_if_t_is_optional_string<SubjectT>>
+SubjectT f$str_replace(const T1 &search, const T2 &replace, const SubjectT &subject,
+                       int64_t &replace_count = StringComponentContext::get().str_replace_count_dummy) {
+  return f$str_replace(search, replace, subject.val(), replace_count);
+}
+
+inline string f$str_ireplace(const string &, const string &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
+  php_critical_error("call to unsupported function");
+}
+
+template<typename T1, typename T2>
+string f$str_ireplace(const array<T1> &, const array<T2> &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
+  php_critical_error("call to unsupported function");
+}
+
+inline string f$str_ireplace(const mixed &, const mixed &, const string &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
+  php_critical_error("call to unsupported function");
+}
+
+template<class T1, class T2, class SubjectT, class = enable_if_t_is_optional_string<SubjectT>>
+SubjectT f$str_ireplace(const T1 &search, const T2 &replace, const SubjectT &subject,
+                        int64_t &replace_count = StringComponentContext::get().str_replace_count_dummy) {
+  return f$str_ireplace(search, replace, subject.val(), replace_count);
+}
 
-inline string f$pack(const string &pattern, const array<mixed> &a) {
+inline mixed f$str_ireplace(const mixed &, const mixed &, const mixed &, int64_t & = StringComponentContext::get().str_replace_count_dummy) {
   php_critical_error("call to unsupported function");
 }
 
-inline Optional<array<mixed>> f$unpack(const string &pattern, const string &data) {
+inline int64_t f$similar_text(const string &, const string &, double & = StringComponentContext::get().default_similar_text_percent_stub) {
   php_critical_error("call to unsupported function");
 }
diff --git a/runtime-light/tl/tl-builtins.h b/runtime-light/tl/tl-builtins.h
index 1b524fe2b5..a2e037079e 100644
--- a/runtime-light/tl/tl-builtins.h
+++ b/runtime-light/tl/tl-builtins.h
@@ -14,9 +14,6 @@
 #include "runtime-light/stdlib/rpc/rpc-api.h"
 #include "runtime-light/stdlib/rpc/rpc-tl-defs.h"
 
-// TODO: get rid of it here
-#define CHECK_EXCEPTION(action)
-
 void register_tl_storers_table_and_fetcher(const array<tl_storer_ptr> &gen$ht, tl_fetch_wrapper_ptr gen$t_ReqResult_fetch);
 
 int32_t tl_parse_save_pos();
diff --git a/runtime-light/utils/to-array-processor.h b/runtime-light/utils/to-array-processor.h
index 1824313c0b..32072472c4 100644
--- a/runtime-light/utils/to-array-processor.h
+++ b/runtime-light/utils/to-array-processor.h
@@ -8,7 +8,7 @@
 
 #include "common/mixin/not_copyable.h"
 #include "common/smart_ptrs/singleton.h"
-#include "runtime-core/runtime-core.h"
+#include "runtime-core/core-types/definition/null_coalesce.h"
 
 class ShapeKeyDemangle : vk::not_copyable {
 public:
diff --git a/tests/phpt/fork/007_fork_instance.php b/tests/phpt/fork/007_fork_instance.php
index a04bc14ade..5161bb97f8 100644
--- a/tests/phpt/fork/007_fork_instance.php
+++ b/tests/phpt/fork/007_fork_instance.php
@@ -1,4 +1,4 @@
-@ok k2_skip
+@ok
 <?php
 
 require_once 'kphp_tester_include.php';