diff --git a/CHANGES.md b/CHANGES.md
index 0ace888..203a7a0 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,5 @@
-Version 4.0.0-dev
------------------
+Version 4.0.0 [[29 Sep 2023]
+----------------------------
 - Increase the minimum requirements to C++ 17 [incompatible change].
 - Change the namespace from `ufal::unilib` to `unilib` [incompatible change].
 - Start using `std::string_view` in the API [incompatible change].
diff --git a/doc/API.md b/doc/API.md
index 257d5df..c52f148 100644
--- a/doc/API.md
+++ b/doc/API.md
@@ -1,4 +1,4 @@
-# UniLib 3.3.2-dev
+# UniLib 4.0.0
 
 The UniLib library is contained in the `unilib` namespace.
 It consists of several independent files, each containing a class with
diff --git a/gen/Makefile b/gen/Makefile
index 258aff8..bf06b21 100644
--- a/gen/Makefile
+++ b/gen/Makefile
@@ -8,7 +8,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 TARGETS=Makefile.include unicode.cpp unicode.h uninorms.cpp uninorms.h unistrip.cpp unistrip.h utf.h version.h
-UNILIB=3.3.2-dev
+UNILIB=4.0.0
 UNICODE=15.1.0
 
 all: generate.pl Makefile $(wildcard data/*.txt) $(TARGETS:%=template/%)
diff --git a/unilib/Makefile.include b/unilib/Makefile.include
index 67d6e81..c9b4a7d 100644
--- a/unilib/Makefile.include
+++ b/unilib/Makefile.include
@@ -7,7 +7,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-UNILIB_VERSION := 3.3.2-dev
+UNILIB_VERSION := 4.0.0
 UNILIB_UNICODE_VERSION := 15.1.0
 
 UNILIB_OBJECTS := unicode uninorms unistrip
diff --git a/unilib/unicode.cpp b/unilib/unicode.cpp
index 3d8dc35..9f6467d 100644
--- a/unilib/unicode.cpp
+++ b/unilib/unicode.cpp
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #include "unicode.h"
diff --git a/unilib/unicode.h b/unilib/unicode.h
index b5e12ff..915c789 100644
--- a/unilib/unicode.h
+++ b/unilib/unicode.h
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #pragma once
diff --git a/unilib/uninorms.cpp b/unilib/uninorms.cpp
index 973ed76..29554dd 100644
--- a/unilib/uninorms.cpp
+++ b/unilib/uninorms.cpp
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #include "uninorms.h"
diff --git a/unilib/uninorms.h b/unilib/uninorms.h
index 1f5fd25..1106ab6 100644
--- a/unilib/uninorms.h
+++ b/unilib/uninorms.h
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #pragma once
diff --git a/unilib/unistrip.cpp b/unilib/unistrip.cpp
index 1a52ddc..21fdf82 100644
--- a/unilib/unistrip.cpp
+++ b/unilib/unistrip.cpp
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #include "unistrip.h"
diff --git a/unilib/unistrip.h b/unilib/unistrip.h
index 53946d9..130660a 100644
--- a/unilib/unistrip.h
+++ b/unilib/unistrip.h
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #pragma once
diff --git a/unilib/utf.h b/unilib/utf.h
index 6beebde..41a5315 100644
--- a/unilib/utf.h
+++ b/unilib/utf.h
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #pragma once
diff --git a/unilib/version.h b/unilib/version.h
index f0e3380..9e591f2 100644
--- a/unilib/version.h
+++ b/unilib/version.h
@@ -7,7 +7,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 //
-// UniLib version: 3.3.2-dev
+// UniLib version: 4.0.0
 // Unicode version: 15.1.0
 
 #pragma once
@@ -42,7 +42,7 @@ std::string version::to_string() {
 }
 
 version version::current() {
-  return {3, 3, 2, "dev"};
+  return {4, 0, 0, ""};
 }
 
 } // namespace unilib