diff --git a/CHANGES.md b/CHANGES.md
index ce1efa3076..31306a4487 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,10 @@
+## Changes in 0.22.3 (2022-02-24)
+
+🐛 Bugfixes
+
+- Thread Safety: Replace all objc_sync_enter/exit methods with recursive locks. ([#5675](https://github.com/vector-im/element-ios/issues/5675))
+
+
 ## Changes in 0.22.2 (2022-02-22)
 
 🙌 Improvements
diff --git a/MatrixSDK.podspec b/MatrixSDK.podspec
index fb91ceec70..c041f151c7 100644
--- a/MatrixSDK.podspec
+++ b/MatrixSDK.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name         = "MatrixSDK"
-  s.version      = "0.22.2"
+  s.version      = "0.22.3"
   s.summary      = "The iOS SDK to build apps compatible with Matrix (https://www.matrix.org)"
 
   s.description  = <<-DESC
diff --git a/MatrixSDK/Data/EventTimeline/Thread/MXThreadEventTimeline.swift b/MatrixSDK/Data/EventTimeline/Thread/MXThreadEventTimeline.swift
index c96025967d..0dc5a28af9 100644
--- a/MatrixSDK/Data/EventTimeline/Thread/MXThreadEventTimeline.swift
+++ b/MatrixSDK/Data/EventTimeline/Thread/MXThreadEventTimeline.swift
@@ -55,6 +55,7 @@ public class MXThreadEventTimeline: NSObject, MXEventTimeline {
     
     /// The current pending request
     private var currentHttpOperation: MXHTTPOperation?
+    private let lockListeners = NSRecursiveLock()
     
     private lazy var threadEventFilter: MXRoomEventFilter = {
         let filter = MXRoomEventFilter()
@@ -439,9 +440,9 @@ public class MXThreadEventTimeline: NSObject, MXEventTimeline {
     
     /// Thread safe access to listeners array
     private func synchronizeListeners(_ block: () -> Void) {
-        objc_sync_enter(listeners)
+        lockListeners.lock()
+        defer { lockListeners.unlock() }
         block()
-        objc_sync_exit(listeners)
     }
     
     private func fixRoomId(inEvents events: [MXEvent]) {
diff --git a/MatrixSDK/MatrixSDKVersion.m b/MatrixSDK/MatrixSDKVersion.m
index 59fea862a0..2e34709006 100644
--- a/MatrixSDK/MatrixSDKVersion.m
+++ b/MatrixSDK/MatrixSDKVersion.m
@@ -16,4 +16,4 @@
 
 #import <Foundation/Foundation.h>
 
-NSString *const MatrixSDKVersion = @"0.22.2";
+NSString *const MatrixSDKVersion = @"0.22.3";
diff --git a/MatrixSDK/Threads/MXThreadingService.swift b/MatrixSDK/Threads/MXThreadingService.swift
index 499e7a4db2..b98f649218 100644
--- a/MatrixSDK/Threads/MXThreadingService.swift
+++ b/MatrixSDK/Threads/MXThreadingService.swift
@@ -46,6 +46,7 @@ public class MXThreadingService: NSObject {
     
     private weak var session: MXSession?
     
+    private let lockThreads = NSRecursiveLock()
     private var threads: [String: MXThread] = [:]
     private let multicastDelegate: MXMulticastDelegate<MXThreadingServiceDelegate> = MXMulticastDelegate()
     
@@ -110,10 +111,9 @@ public class MXThreadingService: NSObject {
     /// - Parameter identifier: identifier of a thread
     /// - Returns: thread instance if found, nil otherwise
     public func thread(withId identifier: String) -> MXThread? {
-        objc_sync_enter(threads)
-        let result = threads[identifier]
-        objc_sync_exit(threads)
-        return result
+        lockThreads.lock()
+        defer { lockThreads.unlock() }
+        return threads[identifier]
     }
     
     public func createTempThread(withId identifier: String, roomId: String) -> MXThread {
@@ -308,9 +308,9 @@ public class MXThreadingService: NSObject {
     }
     
     private func saveThread(_ thread: MXThread) {
-        objc_sync_enter(threads)
+        lockThreads.lock()
+        defer { lockThreads.unlock() }
         threads[thread.id] = thread
-        objc_sync_exit(threads)
     }
     
     //  MARK: - Delegate
diff --git a/MatrixSDK/Utils/MXMulticastDelegate.swift b/MatrixSDK/Utils/MXMulticastDelegate.swift
index 875ec31720..46fad221ee 100644
--- a/MatrixSDK/Utils/MXMulticastDelegate.swift
+++ b/MatrixSDK/Utils/MXMulticastDelegate.swift
@@ -22,6 +22,7 @@ public class MXMulticastDelegate <T: AnyObject> {
     /// Weakly referenced delegates
     private let delegates: NSHashTable<T> = NSHashTable.weakObjects()
     private let dispatchQueue: DispatchQueue
+    private let lockDelegates = NSRecursiveLock()
     
     /// Initializer
     /// - Parameter dispatchQueue: Queue to invoke delegate methods
@@ -70,9 +71,9 @@ public class MXMulticastDelegate <T: AnyObject> {
     
     /// Thread safe access to delegates array
     private func synchronizeDelegates(_ block: () -> Void) {
-        objc_sync_enter(delegates)
+        lockDelegates.lock()
+        defer { lockDelegates.unlock() }
         block()
-        objc_sync_exit(delegates)
     }
     
     deinit {