diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff0ec9644..769a345d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,14 @@
 Each release usually includes various fixes and improvements.
 The most noteworthy of these, as well as any features and breaking changes, are listed here.
 
+## 4.0.1
+* Updated Lavaplayer to 2.10
+* Updated OSHI to 6.4.8
+* Fix/user data missing field exception in protocol
+* Fix plugin manager not deleting old plugin version
+* Fix not being able to seek when player is paused
+* Removed illegal reflection notice
+
 ## 4.0.0
 * Lavalink now requires Java 17 or higher to run
 * **Removal of all websocket messages sent by the client. Everything is now done via [REST](../api/rest.md)**
diff --git a/LavalinkServer/src/main/java/lavalink/server/Launcher.kt b/LavalinkServer/src/main/java/lavalink/server/Launcher.kt
index 6ae103fe7..8252b9a47 100644
--- a/LavalinkServer/src/main/java/lavalink/server/Launcher.kt
+++ b/LavalinkServer/src/main/java/lavalink/server/Launcher.kt
@@ -123,7 +123,6 @@ object Launcher {
         }
 
         val parent = launchPluginBootstrap()
-        log.info("You can safely ignore the big red warning about illegal reflection. See https://github.com/lavalink-devs/Lavalink/issues/295")
         launchMain(parent, args)
     }
 
diff --git a/LavalinkServer/src/main/java/lavalink/server/bootstrap/PluginManager.kt b/LavalinkServer/src/main/java/lavalink/server/bootstrap/PluginManager.kt
index 6f168a1b6..d34d61628 100644
--- a/LavalinkServer/src/main/java/lavalink/server/bootstrap/PluginManager.kt
+++ b/LavalinkServer/src/main/java/lavalink/server/bootstrap/PluginManager.kt
@@ -10,15 +10,16 @@ import java.io.InputStream
 import java.net.URL
 import java.net.URLClassLoader
 import java.nio.channels.Channels
-import java.nio.file.Files
 import java.util.*
 import java.util.jar.JarFile
-import java.util.regex.Pattern
-
 
 @SpringBootApplication
 class PluginManager(val config: PluginsConfig) {
 
+    companion object {
+        private val log: Logger = LoggerFactory.getLogger(PluginManager::class.java)
+    }
+
     final val pluginManifests: MutableList<PluginManifest> = mutableListOf()
     var classLoader: ClassLoader = PluginManager::class.java.classLoader
 
@@ -35,14 +36,13 @@ class PluginManager(val config: PluginsConfig) {
         val directory = File(config.pluginsDir)
         directory.mkdir()
 
-        data class PluginJar(val name: String, val version: String, val file: File)
+        data class PluginJar(val manifest: PluginManifest, val file: File)
 
-        val pattern = Pattern.compile("(.+)-(.+)\\.jar$")
-        val pluginJars = directory.listFiles()!!.mapNotNull { f ->
-            val matcher = pattern.matcher(f.name)
-            if (!matcher.find()) return@mapNotNull null
-            PluginJar(matcher.group(1), matcher.group(2), f)
-        }
+        val pluginJars = directory.listFiles()!!.filter { it.extension == "jar" }.map {
+            JarFile(it).use {jar ->
+                loadPluginManifests(jar).map { manifest -> PluginJar(manifest, it) }
+            }
+        }.flatten()
 
         data class Declaration(val group: String, val name: String, val version: String, val repository: String)
 
@@ -55,21 +55,22 @@ class PluginManager(val config: PluginsConfig) {
                 ?: if (declaration.snapshot) config.defaultPluginSnapshotRepository else config.defaultPluginRepository
             repository = if (repository.endsWith("/")) repository else "$repository/"
             Declaration(fragments[0], fragments[1], fragments[2], repository)
-        }
+        }.distinctBy { "${it.group}:${it.name}" }
 
         declarations.forEach declarationLoop@{ declaration ->
-            pluginJars.forEach { jar ->
-                if (declaration.name == jar.name) {
-                    if (declaration.version == jar.version) {
-                        // We already have this jar so don't redownload it
-                        return@declarationLoop
-                    }
-
-                    // Delete jar of different versions
-                    if (!jar.file.delete()) throw RuntimeException("Failed to delete ${jar.file.path}")
-                    log.info("Deleted ${jar.file.path}")
+            var hasVersion = false
+            pluginJars.forEach pluginLoop@{ jar ->
+                if (declaration.version == jar.manifest.version && !hasVersion) {
+                    hasVersion = true
+                    // We already have this jar so don't redownload it
+                    return@pluginLoop
                 }
+
+                // Delete jar of different versions
+                if (!jar.file.delete()) throw RuntimeException("Failed to delete ${jar.file.path}")
+                log.info("Deleted ${jar.file.path}")
             }
+            if (hasVersion) return@declarationLoop
 
             val url = declaration.run { "$repository${group.replace(".", "/")}/$name/$version/$name-$version.jar" }
             val file = File(directory, declaration.run { "$name-$version.jar" })
@@ -87,7 +88,11 @@ class PluginManager(val config: PluginsConfig) {
     private fun readClasspathManifests(): List<PluginManifest> {
         return PathMatchingResourcePatternResolver()
             .getResources("classpath*:lavalink-plugins/*.properties")
-            .map { r -> parsePluginManifest(r.inputStream) }
+            .map map@{ r ->
+                val manifest = parsePluginManifest(r.inputStream)
+                log.info("Found plugin '${manifest.name}' version ${manifest.version}")
+                return@map manifest
+            }
     }
 
     private fun loadJars(): List<PluginManifest> {
@@ -95,8 +100,7 @@ class PluginManager(val config: PluginsConfig) {
         if (!directory.isDirectory) return emptyList()
         val jarsToLoad = mutableListOf<File>()
 
-        Files.list(File(config.pluginsDir).toPath()).forEach { path ->
-            val file = path.toFile()
+        directory.listFiles()?.forEach { file ->
             if (!file.isFile) return@forEach
             if (file.extension != "jar") return@forEach
             jarsToLoad.add(file)
@@ -111,7 +115,6 @@ class PluginManager(val config: PluginsConfig) {
         classLoader = cl
 
         val manifests = mutableListOf<PluginManifest>()
-
         jarsToLoad.forEach { file ->
             try {
                 manifests.addAll(loadJar(file, cl))
@@ -124,31 +127,43 @@ class PluginManager(val config: PluginsConfig) {
         return manifests
     }
 
-    private fun loadJar(file: File, cl: URLClassLoader): MutableList<PluginManifest> {
+    private fun loadJar(file: File, cl: URLClassLoader): List<PluginManifest> {
         var classCount = 0
         val jar = JarFile(file)
+        var manifests:  List<PluginManifest>
+
+        jar.use {
+            manifests = loadPluginManifests(jar)
+            if (manifests.isEmpty()) {
+                throw RuntimeException("No plugin manifest found in ${file.path}")
+            }
+            val allowedPaths = manifests.map { it.path.replace(".", "/") }
+
+            jar.entries().asIterator().forEach { entry ->
+                if (entry.isDirectory) return@forEach
+                if (!entry.name.endsWith(".class")) return@forEach
+                if (!allowedPaths.any { entry.name.startsWith(it) }) return@forEach
+                cl.loadClass(entry.name.dropLast(6).replace("/", "."))
+                classCount++
+            }
+        }
+
+        log.info("Loaded ${file.name} ($classCount classes)")
+        return manifests
+    }
+
+    private fun loadPluginManifests(jar: JarFile): List<PluginManifest> {
         val manifests = mutableListOf<PluginManifest>()
 
         jar.entries().asIterator().forEach { entry ->
             if (entry.isDirectory) return@forEach
             if (!entry.name.startsWith("lavalink-plugins/")) return@forEach
             if (!entry.name.endsWith(".properties")) return@forEach
-            manifests.add(parsePluginManifest(jar.getInputStream(entry)))
-        }
 
-        if (manifests.isEmpty()) {
-            throw RuntimeException("No plugin manifest found in ${file.path}")
+            val manifest = parsePluginManifest(jar.getInputStream(entry))
+            log.info("Found plugin '${manifest.name}' version ${manifest.version}")
+            manifests.add(manifest)
         }
-        val allowedPaths = manifests.map { it.path.replace(".", "/") }
-
-        jar.entries().asIterator().forEach { entry ->
-            if (entry.isDirectory) return@forEach
-            if (!entry.name.endsWith(".class")) return@forEach
-            if (!allowedPaths.any { entry.name.startsWith(it) }) return@forEach
-            cl.loadClass(entry.name.dropLast(6).replace("/", "."))
-            classCount++
-        }
-        log.info("Loaded ${file.name} ($classCount classes)")
         return manifests
     }
 
@@ -160,11 +175,6 @@ class PluginManager(val config: PluginsConfig) {
         val name = props.getProperty("name") ?: throw RuntimeException("Manifest is missing 'name'")
         val path = props.getProperty("path") ?: throw RuntimeException("Manifest is missing 'path'")
         val version = props.getProperty("version") ?: throw RuntimeException("Manifest is missing 'version'")
-        log.info("Found plugin '$name' version $version")
         return PluginManifest(name, path, version)
     }
-
-    companion object {
-        private val log: Logger = LoggerFactory.getLogger(PluginManager::class.java)
-    }
 }
\ No newline at end of file
diff --git a/LavalinkServer/src/main/java/lavalink/server/config/WebsocketConfig.kt b/LavalinkServer/src/main/java/lavalink/server/config/WebsocketConfig.kt
index fbf73b34e..16c57eb61 100644
--- a/LavalinkServer/src/main/java/lavalink/server/config/WebsocketConfig.kt
+++ b/LavalinkServer/src/main/java/lavalink/server/config/WebsocketConfig.kt
@@ -2,18 +2,32 @@ package lavalink.server.config
 
 import lavalink.server.io.HandshakeInterceptorImpl
 import lavalink.server.io.SocketServer
+import org.slf4j.LoggerFactory
 import org.springframework.context.annotation.Configuration
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RestController
 import org.springframework.web.socket.config.annotation.EnableWebSocket
 import org.springframework.web.socket.config.annotation.WebSocketConfigurer
 import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry
 
 @Configuration
 @EnableWebSocket
+@RestController
 class WebsocketConfig(
     private val server: SocketServer,
     private val handshakeInterceptor: HandshakeInterceptorImpl,
 ) : WebSocketConfigurer {
+
+    companion object {
+        private val log = LoggerFactory.getLogger(WebsocketConfig::class.java)
+    }
+
     override fun registerWebSocketHandlers(registry: WebSocketHandlerRegistry) {
         registry.addHandler(server, "/v4/websocket").addInterceptors(handshakeInterceptor)
     }
+
+    @GetMapping("/", "/v3/websocket")
+    fun oldWebsocket() {
+        log.warn("This is the old Lavalink websocket endpoint. Please use /v4/websocket instead. If you are using a client library, please update it to a Lavalink v4 compatible version or use Lavalink v3 instead.")
+    }
 }
diff --git a/LavalinkServer/src/main/java/lavalink/server/io/StatsCollector.kt b/LavalinkServer/src/main/java/lavalink/server/io/StatsCollector.kt
index 16633e405..4623851ff 100644
--- a/LavalinkServer/src/main/java/lavalink/server/io/StatsCollector.kt
+++ b/LavalinkServer/src/main/java/lavalink/server/io/StatsCollector.kt
@@ -49,6 +49,10 @@ class StatsCollector(val socketServer: SocketServer) {
     private val processRecentCpuUsage: Double
         get() {
             val p = os.getProcess(os.processId)
+            if (p == null) {
+                log.warn("Failed to get process stats. Process was null.")
+                return 0.0
+            }
 
             val output: Double = if (cpuTime != 0.0) {
                 val uptimeDiff = p.upTime - uptime
diff --git a/LavalinkServer/src/main/java/lavalink/server/player/PlayerRestHandler.kt b/LavalinkServer/src/main/java/lavalink/server/player/PlayerRestHandler.kt
index 6a837dbf5..4f4831078 100644
--- a/LavalinkServer/src/main/java/lavalink/server/player/PlayerRestHandler.kt
+++ b/LavalinkServer/src/main/java/lavalink/server/player/PlayerRestHandler.kt
@@ -150,7 +150,7 @@ class PlayerRestHandler(
         // we handle position differently for playing new tracks
         playerUpdate.position.takeIfPresent { encodedTrack is Omissible.Omitted && identifier is Omissible.Omitted }
             ?.let {
-                if (player.isPlaying) {
+                if (player.track != null) {
                     player.seekTo(it)
                     SocketServer.sendPlayerUpdate(context, player)
                 }
diff --git a/build.gradle.kts b/build.gradle.kts
index 98e606842..cd938efea 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -54,7 +54,7 @@ subprojects {
                         val snapshots = "https://maven.lavalink.dev/snapshots"
                         val releases = "https://maven.lavalink.dev/releases"
 
-                        maven(if ((version as String).endsWith("-SNAPSHOT")) releases else snapshots) {
+                        maven(if ((version as String).endsWith("-SNAPSHOT")) snapshots else releases) {
                             credentials {
                                 password = findProperty("MAVEN_PASSWORD") as String?
                                 username = findProperty("MAVEN_USERNAME") as String?
diff --git a/docs/changelog/v4.md b/docs/changelog/v4.md
index e7db702f5..ad762f496 100644
--- a/docs/changelog/v4.md
+++ b/docs/changelog/v4.md
@@ -1,3 +1,11 @@
+## 4.0.1
+* Updated Lavaplayer to 2.10
+* Updated OSHI to 6.4.8
+* Fix/user data missing field exception in protocol
+* Fix plugin manager not deleting old plugin version
+* Fix not being able to seek when player is paused
+* Removed illegal reflection notice
+
 ## v4.0.0
 * Lavalink now requires Java 17 or higher to run
 * **Removal of all websocket messages sent by the client. Everything is now done via [REST](../api/rest.md)**
diff --git a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/loadResult.kt b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/loadResult.kt
index f1b902d1f..c5c348c3c 100644
--- a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/loadResult.kt
+++ b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/loadResult.kt
@@ -133,7 +133,7 @@ data class PlaylistInfo(
 @Serializable
 data class Playlist(
     val info: PlaylistInfo,
-    val pluginInfo: JsonObject,
+    val pluginInfo: JsonObject = JsonObject(emptyMap()),
     val tracks: List<Track>
 ) : LoadResult.Data {
 
diff --git a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
index a9fbb1aaf..6da7cd5b7 100644
--- a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
+++ b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/omissible.kt
@@ -73,7 +73,7 @@ class OmissableSerializer<T>(private val childSerializer: KSerializer<T>) : KSer
 }
 
 @OptIn(ExperimentalContracts::class)
-fun <T : Any> Omissible<T>.isPresent(): Boolean {
+fun <T : Any?> Omissible<T>.isPresent(): Boolean {
     contract {
         returns(true) implies (this@isPresent is Omissible.Present<T>)
     }
@@ -81,7 +81,7 @@ fun <T : Any> Omissible<T>.isPresent(): Boolean {
 }
 
 @OptIn(ExperimentalContracts::class)
-fun <T : Any> Omissible<T>.isOmitted(): Boolean {
+fun <T : Any?> Omissible<T>.isOmitted(): Boolean {
     contract {
         returns(true) implies (this@isOmitted is Omissible.Omitted<T>)
     }
diff --git a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/player.kt b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/player.kt
index b9ddf2733..19c7a7917 100644
--- a/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/player.kt
+++ b/protocol/src/commonMain/kotlin/dev/arbjerg/lavalink/protocol/v4/player.kt
@@ -31,8 +31,8 @@ data class Player(
 data class Track(
     val encoded: String,
     val info: TrackInfo,
-    val pluginInfo: JsonObject,
-    val userData: JsonObject
+    val pluginInfo: JsonObject = JsonObject(emptyMap()),
+    val userData: JsonObject = JsonObject(emptyMap())
 ) : LoadResult.Data {
 
     /**
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 459f9affe..861cb22c7 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -36,7 +36,7 @@ fun VersionCatalogBuilder.spring() {
 }
 
 fun VersionCatalogBuilder.voice() {
-    version("lavaplayer", "2.0.4")
+    version("lavaplayer", "2.1.0")
 
     library("lavaplayer",            "dev.arbjerg", "lavaplayer").versionRef("lavaplayer")
     library("lavaplayer-ip-rotator", "dev.arbjerg", "lavaplayer-ext-youtube-rotator").versionRef("lavaplayer")
@@ -76,7 +76,7 @@ fun VersionCatalogBuilder.common() {
 
     library("logback",        "ch.qos.logback",       "logback-classic").version("1.4.7")
     library("sentry-logback", "io.sentry",            "sentry-logback").version("6.22.0")
-    library("oshi",           "com.github.oshi",      "oshi-core").version("6.4.3")
+    library("oshi",           "com.github.oshi",      "oshi-core").version("6.4.8")
 }
 
 fun VersionCatalogBuilder.other() {