diff --git a/3rdparty/libjpeg/CMakeLists.txt b/3rdparty/libjpeg/CMakeLists.txt
index c0524cc38..69a71e416 100644
--- a/3rdparty/libjpeg/CMakeLists.txt
+++ b/3rdparty/libjpeg/CMakeLists.txt
@@ -27,7 +27,6 @@ endif()
 
 ocv_warnings_disable(CMAKE_C_FLAGS -Wcast-align -Wshadow -Wunused -Wshift-negative-value -Wimplicit-fallthrough)
 ocv_warnings_disable(CMAKE_C_FLAGS -Wunused-parameter) # clang
-ocv_warnings_disable(CMAKE_C_FLAGS /wd4013 /wd4244 /wd4267) # vs2005
 
 set_target_properties(${JPEG_LIBRARY}
   PROPERTIES OUTPUT_NAME ${JPEG_LIBRARY}
diff --git a/3rdparty/zlib/CMakeLists.txt b/3rdparty/zlib/CMakeLists.txt
index 9758861a6..9e654ba92 100644
--- a/3rdparty/zlib/CMakeLists.txt
+++ b/3rdparty/zlib/CMakeLists.txt
@@ -81,7 +81,6 @@ set_target_properties(${ZLIB_LIBRARY} PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
 
 ocv_warnings_disable(CMAKE_C_FLAGS -Wshorten-64-to-32 -Wattributes -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wshift-negative-value
     -Wundef  # _LFS64_LARGEFILE is not defined
-    /wd4267  # MSVS 2015 (x64) + zlib 1.2.11
     -Wimplicit-fallthrough
 )
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d95e5db16..db185453d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -617,11 +617,6 @@ endif()
 
 ocv_cmake_hook(POST_CMAKE_BUILD_OPTIONS)
 
-# --- Python Support ---
-if(NOT IOS)
-  include(cmake/OpenCVDetectPython.cmake)
-endif()
-
 include(cmake/OpenCVCompilerOptions.cmake)
 
 ocv_cmake_hook(POST_COMPILER_OPTIONS)
diff --git a/cmake/OpenCVDetectCXXCompiler.cmake b/cmake/OpenCVDetectCXXCompiler.cmake
index 7f229cde9..92e204a5b 100644
--- a/cmake/OpenCVDetectCXXCompiler.cmake
+++ b/cmake/OpenCVDetectCXXCompiler.cmake
@@ -171,7 +171,7 @@ elseif(MSVC)
     set(OpenCV_RUNTIME vc15)
   elseif(MSVC_VERSION MATCHES "^192[0-9]$")
     set(OpenCV_RUNTIME vc16)
-  elseif(MSVC_VERSION MATCHES "^193[0-9]$")
+  elseif(MSVC_VERSION MATCHES "^19[34][0-9]$")
     set(OpenCV_RUNTIME vc17)
   else()
     message(WARNING "OpenCV does not recognize MSVC_VERSION \"${MSVC_VERSION}\". Cannot set OpenCV_RUNTIME")
diff --git a/modules/core/include/opencv2/core/ocl.hpp b/modules/core/include/opencv2/core/ocl.hpp
index 4503fa00d..642b0508d 100644
--- a/modules/core/include/opencv2/core/ocl.hpp
+++ b/modules/core/include/opencv2/core/ocl.hpp
@@ -302,21 +302,6 @@ public:
 
     void release();
 
-    class CV_EXPORTS UserContext {
-    public:
-        virtual ~UserContext();
-    };
-    template <typename T>
-    inline void setUserContext(const std::shared_ptr<T>& userContext) {
-        setUserContext(typeid(T), userContext);
-    }
-    template <typename T>
-    inline std::shared_ptr<T> getUserContext() {
-        return std::dynamic_pointer_cast<T>(getUserContext(typeid(T)));
-    }
-    void setUserContext(std::type_index typeId, const std::shared_ptr<UserContext>& userContext);
-    std::shared_ptr<UserContext> getUserContext(std::type_index typeId);
-
     struct Impl;
     inline Impl* getImpl() const { return (Impl*)p; }
     inline bool empty() const { return !p; }
diff --git a/modules/core/src/ocl_disabled.impl.hpp b/modules/core/src/ocl_disabled.impl.hpp
index a217979a1..0ba30d024 100644
--- a/modules/core/src/ocl_disabled.impl.hpp
+++ b/modules/core/src/ocl_disabled.impl.hpp
@@ -177,11 +177,6 @@ void* Context::getOpenCLContextProperty(int /*propertyId*/) const { OCL_NOT_AVAI
 bool Context::useSVM() const { return false; }
 void Context::setUseSVM(bool enabled) { }
 
-Context::UserContext::~UserContext() { }
-
-void Context::setUserContext(std::type_index /*typeId*/, const std::shared_ptr<Context::UserContext>& /*userContext*/) { OCL_NOT_AVAILABLE(); }
-std::shared_ptr<Context::UserContext> Context::getUserContext(std::type_index /*typeId*/) { OCL_NOT_AVAILABLE(); }
-
 /* static */ Context Context::fromHandle(void* context) { OCL_NOT_AVAILABLE(); }
 /* static */ Context Context::fromDevice(const ocl::Device& device) { OCL_NOT_AVAILABLE(); }
 /* static */ Context Context::create(const std::string& configuration) { OCL_NOT_AVAILABLE(); }
diff --git a/modules/imgcodecs/src/macosx_conversions.mm b/modules/imgcodecs/src/macosx_conversions.mm
index 0023e06260..8a4bc0b211 100644
--- a/modules/imgcodecs/src/macosx_conversions.mm
+++ b/modules/imgcodecs/src/macosx_conversions.mm
@@ -9,6 +9,7 @@ CV_EXPORTS NSImage* MatToNSImage(const cv::Mat& image);
 CV_EXPORTS void NSImageToMat(const NSImage* image, cv::Mat& m, bool alphaExist);
 
 NSImage* MatToNSImage(const cv::Mat& image) {
+#if !NSIMAGE_UNAVAILABLE_MACCATALYST
     // Creating CGImage from cv::Mat
     CGImageRef imageRef = MatToCGImage(image);
 
@@ -17,9 +18,22 @@ NSImage* MatToNSImage(const cv::Mat& image) {
     CGImageRelease(imageRef);
 
     return nsImage;
+#else
+    @throw [NSException 
+            exceptionWithName:@"NSGenericException" 
+            reason:@"NSImage is not supported on Mac Catalyst"
+            userInfo:nil];
+#endif
 }
 
 void NSImageToMat(const NSImage* image, cv::Mat& m, bool alphaExist) {
+#if !NSIMAGE_UNAVAILABLE_MACCATALYST
     CGImageRef imageRef = [image CGImageForProposedRect:NULL context:NULL hints:NULL];
     CGImageToMat(imageRef, m, alphaExist);
+#else
+    @throw [NSException 
+            exceptionWithName:@"NSGenericException" 
+            reason:@"NSImage is not supported on Mac Catalyst"
+            userInfo:nil];
+#endif
 }
diff --git a/samples/dnn/dnn_model_runner/dnn_conversion/requirements.txt b/samples/dnn/dnn_model_runner/dnn_conversion/requirements.txt
deleted file mode 100644
index 6887c2ab2..000000000
--- a/samples/dnn/dnn_model_runner/dnn_conversion/requirements.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-# Python 3.7.5
-onnx>=1.7.0
-numpy>=1.19.1
-
-torch>=1.5.1
-torchvision>=0.6.1
-
-tensorflow>=2.1.0
-tensorflow-gpu>=2.1.0
-
-paddlepaddle>=2.0.0
-paddlepaddle-gpu>=2.0.0
-paddlehub>=2.1.0
-paddle2onnx>=0.5.1
-paddleseg>=2.0.0
\ No newline at end of file