diff --git a/Docs/src/manual/Ogre3.0.Changes.md b/Docs/src/manual/Ogre3.0.Changes.md
index d764cfacad8..34175240d21 100644
--- a/Docs/src/manual/Ogre3.0.Changes.md
+++ b/Docs/src/manual/Ogre3.0.Changes.md
@@ -46,4 +46,37 @@ Make sure to upgrade to latest CMake scripts if you're using them; to be ready f
 
 Default material BRDF settings have changed in 3.0; thus materials will look different.
 
-See [PBR / PBS Changes in 3.0](@ref PBSChangesIn30) to how make them look like they did in 2.3 and what these changes mean.
\ No newline at end of file
+See [PBR / PBS Changes in 3.0](@ref PBSChangesIn30) to how make them look like they did in 2.3 and what these changes mean.
+
+## Move to C++11 and general cleanup
+
+Lots of dead \& long-deprecated code was removed.
+See [Resolving Merge Conflicts in Ogre-Next 3.0](@ref ResolvingMergeConflicts30) for more help with C++11 changes.
+
+ - Remove D3D9
+ - Remove Terrain
+ - Remove RTShaderSystem
+ - Remove NaCL
+ - Remove dead SceneManagers
+ - Remove `( void )` from empty functions
+ - Remove StaticGeometry
+ - Remove files under `Deprecated/` folders
+ - Move to C++11
+   - Remove code under `__cplusplus` that uses `< 201103L` `>= 201103L` or numbers below 201103L
+ - Math::Log2 should use log2
+ - All virtuals must have `overload` keyword
+ - Remove `HardwareUniformBuffer`, `HardwareCounterBuffer`
+ - Fix many warnings.
+ - Clean up Media folder and remove unused stuff from Ogre samples.
+ - Add ASAN CMake option.
+ - Use OGRE_DEPRECATED.
+ - Add cmake option to embed debug level into OgreBuildSettings.
+    - Bakes OGRE_DEBUG_MODE into OgreBuildSettings.h; which is on by default on Ninja/GNU Make generators and disabled for the rest.
+ - Pass cookie to Ogre Root initialization to catch obvious ABI errors. Each library could call checkAbiCookie on initialization to avoid problems
+ - Default to clang's ld linker on Linux, i.e. `set( CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld" )`
+ - Remove `OgreShadowVolumeExtrudeProgram.cpp`
+ - Deprecate `SceneManager::setFog`
+ - Remove `getShadowCasterVertex`
+ - Remove memory allocator stuff (see Ogre 1.x)
+ - Remove nedmalloc
+ - Typedef SharedPtr to std::shared_ptr (see Ogre 1.x)
diff --git a/Docs/src/manual/ResolvingMergeConflictsIn3.0.md b/Docs/src/manual/ResolvingMergeConflictsIn3.0.md
index a4ddc032e04..047f2e6d0f2 100644
--- a/Docs/src/manual/ResolvingMergeConflictsIn3.0.md
+++ b/Docs/src/manual/ResolvingMergeConflictsIn3.0.md
@@ -7,9 +7,9 @@ In Ogre-Next 3.0 we performed multiple changes that affected nearly the entire c
  - Lots of warnings were fixed
  - Clang format 13 was applied to the entire codebase
 
-Users who run a customized version of Ogre-Next may found rebasing to the latest version a near impossible job due to the sheer amount of minor merge conflicts.
+Users who run a forked/customized version of Ogre-Next may found rebasing to the latest version a near impossible job due to the sheer amount of *minor* merge conflicts.
 
-To perform this task with more easily, we recommend the following:
+To perform this task more easily, we recommend the following:
 
  1. Merge your changes with `master` branch (or 3.0 when it appears)
  2. Resolve all conflicts with `your code`
@@ -69,7 +69,7 @@ void moreFunctions()
 }
 ```
 
-After applying Clang format, everything that follows will indent (and likely the code will not compile):
+After applying Clang format, everything that follows will indent (and likely the code will not compile) which make much easier to spot where the problem went wrong:
 
 ```cpp
 void myFuntion( int a )
@@ -90,12 +90,12 @@ void myFuntion( int a )
 	}
 ```
 
-If you find after merging and applying clang format that there is massive added or removed indentation; start from the top and find the first occurrence of this change and start looking for the missing brace.
+If you find after merging and applying clang format that there is massive indentation being added (or removed); start from the top and find the first occurrence of this change and start looking for the missing brace.
 
 
 # Batch Script
 
-The following bash script will run clang-format on all files with the right extensions in the current folder and recursively in its subdirectories
+The following bash script will run clang-format on all files with the right extensions in the current folder and recursively in its sub-directories.
 
 ```bash
 FILES=$(find . -name "*.mm" -o -name "*.h" -o -name "*.cpp")
@@ -105,4 +105,6 @@ do
   echo "Formatting \"$file\""
   clang-format-13 -i "$file"
 done
-```
\ No newline at end of file
+```
+
+You can also look at our python script in [.github/workflows/run_clang_format.py](https://github.com/OGRECave/ogre-next/blob/879a86fd4d1e7274af67b37628f29d6ad06a7d79/.github/workflows/run_clang_format.py) if you prefer Python instead.
\ No newline at end of file
diff --git a/OgreMain/include/OgreMaterial.h b/OgreMain/include/OgreMaterial.h
index 8f9ae048ae8..55e62bb1de7 100644
--- a/OgreMain/include/OgreMaterial.h
+++ b/OgreMain/include/OgreMaterial.h
@@ -459,6 +459,7 @@ namespace Ogre
             property there.
         @see Pass::setFog
         */
+        OGRE_DEPRECATED_VER( 3 )
         void setFog( bool overrideScene, FogMode mode = FOG_NONE,
                      const ColourValue &colour = ColourValue::White, Real expDensity = Real( 0.001 ),
                      Real linearStart = 0.0, Real linearEnd = 1.0 );
diff --git a/OgreMain/include/OgrePass.h b/OgreMain/include/OgrePass.h
index f95141b93fe..a1e533845ff 100644
--- a/OgreMain/include/OgrePass.h
+++ b/OgreMain/include/OgrePass.h
@@ -608,41 +608,42 @@ namespace Ogre
             linearEnd Distance in world units at which linear fog becomes completely opaque.
             Only applicable if mode is FOG_LINEAR.
         */
+        OGRE_DEPRECATED_VER( 3 )
         void setFog( bool overrideScene, FogMode mode = FOG_NONE,
                      const ColourValue &colour = ColourValue::White, Real expDensity = Real( 0.001 ),
                      Real linearStart = 0.0, Real linearEnd = 1.0 );
 
         /** Returns true if this pass is to override the scene fog settings.
          */
-        bool getFogOverride() const;
+        OGRE_DEPRECATED_VER( 3 ) bool getFogOverride() const;
 
         /** Returns the fog mode for this pass.
             @note
             Only valid if getFogOverride is true.
         */
-        FogMode getFogMode() const;
+        OGRE_DEPRECATED_VER( 3 ) FogMode getFogMode() const;
 
         /** Returns the fog colour for the scene.
          */
-        const ColourValue &getFogColour() const;
+        OGRE_DEPRECATED_VER( 3 ) const ColourValue &getFogColour() const;
 
         /** Returns the fog start distance for this pass.
             @note
             Only valid if getFogOverride is true.
         */
-        Real getFogStart() const;
+        OGRE_DEPRECATED_VER( 3 ) Real getFogStart() const;
 
         /** Returns the fog end distance for this pass.
             @note
             Only valid if getFogOverride is true.
         */
-        Real getFogEnd() const;
+        OGRE_DEPRECATED_VER( 3 ) Real getFogEnd() const;
 
         /** Returns the fog density for this pass.
             @note
             Only valid if getFogOverride is true.
         */
-        Real getFogDensity() const;
+        OGRE_DEPRECATED_VER( 3 ) Real getFogDensity() const;
 
         /// Gets the internal datablock that acts as proxy for us
         HlmsDatablock *_getDatablock() const;
diff --git a/OgreMain/include/OgreSceneManager.h b/OgreMain/include/OgreSceneManager.h
index 68127c42e89..b9e5b5a7c97 100644
--- a/OgreMain/include/OgreSceneManager.h
+++ b/OgreMain/include/OgreSceneManager.h
@@ -1943,6 +1943,8 @@ namespace Ogre
         virtual void _restoreManualHardwareResources();
 
         /** Sets the fogging mode applied to the scene.
+            Deprecated in favour of Atmosphere component. See AtmosphereNpr::setSky.
+
             @remarks
                 This method sets up the scene-wide fogging effect. These settings
                 apply to all geometry rendered, UNLESS the material with which it
@@ -1966,29 +1968,30 @@ namespace Ogre
                 opaque. Only applicable if mode is
                 FOG_LINEAR.
         */
+        OGRE_DEPRECATED_VER( 3 )
         void setFog( FogMode mode = FOG_NONE, const ColourValue &colour = ColourValue::White,
                      Real expDensity = Real( 0.001 ), Real linearStart = Real( 0.0 ),
                      Real linearEnd = Real( 1.0 ) );
 
         /** Returns the fog mode for the scene.
          */
-        virtual FogMode getFogMode() const;
+        OGRE_DEPRECATED_VER( 3 ) virtual FogMode getFogMode() const;
 
         /** Returns the fog colour for the scene.
          */
-        virtual const ColourValue &getFogColour() const;
+        OGRE_DEPRECATED_VER( 3 ) virtual const ColourValue &getFogColour() const;
 
         /** Returns the fog start distance for the scene.
          */
-        virtual Real getFogStart() const;
+        OGRE_DEPRECATED_VER( 3 ) virtual Real getFogStart() const;
 
         /** Returns the fog end distance for the scene.
          */
-        virtual Real getFogEnd() const;
+        OGRE_DEPRECATED_VER( 3 ) virtual Real getFogEnd() const;
 
         /** Returns the fog density for the scene.
          */
-        virtual Real getFogDensity() const;
+        OGRE_DEPRECATED_VER( 3 ) virtual Real getFogDensity() const;
 
         /** Creates a new BillboardSet for use with this scene manager.
             @remarks
diff --git a/OgreMain/include/OgreTechnique.h b/OgreMain/include/OgreTechnique.h
index cd71fe4ae58..ea1b70c45a1 100644
--- a/OgreMain/include/OgreTechnique.h
+++ b/OgreMain/include/OgreTechnique.h
@@ -341,6 +341,7 @@ namespace Ogre
             property there.
         @see Pass::setFog
         */
+        OGRE_DEPRECATED_VER( 3 )
         void setFog( bool overrideScene, FogMode mode = FOG_NONE,
                      const ColourValue &colour = ColourValue::White, Real expDensity = Real( 0.001 ),
                      Real linearStart = 0.0, Real linearEnd = 1.0 );
diff --git a/OgreMain/src/OgreHlmsLowLevel.cpp b/OgreMain/src/OgreHlmsLowLevel.cpp
index 463f8ea894f..739d8b97a9b 100644
--- a/OgreMain/src/OgreHlmsLowLevel.cpp
+++ b/OgreMain/src/OgreHlmsLowLevel.cpp
@@ -283,6 +283,12 @@ namespace Ogre
         mAutoParamDataSource->setCurrentPass( pass );
         mAutoParamDataSource->setCurrentLightList( &renderable->getLights() );
 
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( push, 0 )
+#else
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
         if( pass->getFogOverride() )
         {
             mAutoParamDataSource->setFog( pass->getFogMode(), pass->getFogColour(),
@@ -296,6 +302,11 @@ namespace Ogre
                 mCurrentSceneManager->getFogDensity(), mCurrentSceneManager->getFogStart(),
                 mCurrentSceneManager->getFogEnd() );
         }
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( pop )
+#else
+#    pragma GCC diagnostic pop
+#endif
 
         Pass::ConstTextureUnitStateIterator texIter = pass->getTextureUnitStateIterator();
         size_t unit = 0;
diff --git a/OgreMain/src/OgreMaterialSerializer.cpp b/OgreMain/src/OgreMaterialSerializer.cpp
index e0f04f6d32d..dcc42ec0ecc 100644
--- a/OgreMain/src/OgreMaterialSerializer.cpp
+++ b/OgreMain/src/OgreMaterialSerializer.cpp
@@ -627,6 +627,12 @@ namespace Ogre
                 writeValue( pPass->getPolygonModeOverrideable() ? "on" : "off" );
             }
 
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( push, 0 )
+#else
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
             // fog override
             if( mDefaults || pPass->getFogOverride() != false )
             {
@@ -659,6 +665,11 @@ namespace Ogre
                     }
                 }
             }
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( pop )
+#else
+#    pragma GCC diagnostic pop
+#endif
 
             //  GPU Vertex and Fragment program references and parameters
             if( pPass->hasVertexProgram() )
diff --git a/OgreMain/src/OgreSceneManager.cpp b/OgreMain/src/OgreSceneManager.cpp
index 48626395b71..db54259429c 100644
--- a/OgreMain/src/OgreSceneManager.cpp
+++ b/OgreMain/src/OgreSceneManager.cpp
@@ -229,8 +229,20 @@ namespace Ogre
                 mShadowCasterPlainBlackPass->setDiffuse( ColourValue::Black );
                 mShadowCasterPlainBlackPass->setSelfIllumination( ColourValue::Black );
                 mShadowCasterPlainBlackPass->setSpecular( ColourValue::Black );
+
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( push, 0 )
+#else
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
                 // Override fog
                 mShadowCasterPlainBlackPass->setFog( true, FOG_NONE );
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( pop )
+#else
+#    pragma GCC diagnostic pop
+#endif
                 // no textures or anything else, we will bind vertex programs
                 // every so often though
             }
diff --git a/OgreMain/src/OgreScriptTranslator.cpp b/OgreMain/src/OgreScriptTranslator.cpp
index fa756f954e4..62a51371cec 100644
--- a/OgreMain/src/OgreScriptTranslator.cpp
+++ b/OgreMain/src/OgreScriptTranslator.cpp
@@ -2489,7 +2489,18 @@ namespace Ogre{
                                 ++i2;
                             }
 
-                            mPass->setFog(val, mode, clr, dens, start, end);
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( push, 0 )
+#else
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+                            mPass->setFog( val, mode, clr, dens, start, end );
+#if OGRE_COMPILER == OGRE_COMPILER_MSVC
+#    pragma warning( pop )
+#else
+#    pragma GCC diagnostic pop
+#endif
                         }
                         else
                             compiler->addError(ScriptCompiler::CE_INVALIDPARAMETERS, prop->file, prop->line,