Unofficial and possibly incomplete list of ImageMagick C API changes between
Debian versions 6.2.4.5.dfsg1-2 and 6.3.7.9.dfsg1-1:

* New API functions:
  + AcquireCacheViewIndexes()
  + AcquireCacheViewPixels()
  + AcquireDrawInfo()
  + AcquireExceptionInfo()
  + AcquireFxInfo()
  + AcquireImageInfo()
  + AcquireIndexes()
  + AcquireNexusIndexes()
  + AcquireOneCacheViewPixel()
  + AcquireOneMagickPixel()
  + AcquireOneVirtualPixel()
  + AcquireQuantizeInfo()
  + AcquireQuantumInfo()
  + AcquireResampleFilter()
  + AcquireStreamInfo()
  + AcquireTokenInfo()
  + AcquireUniqueSymbolicLink()
  + AdaptiveBlurImageChannel()
  + AdaptiveBlurImage()
  + AdaptiveResizeImage()
  + AdaptiveSharpenImageChannel()
  + AdaptiveSharpenImage()
  + AddChildToXMLTree()
  + AddNoiseImageChannel()
  + AddPathToXMLTree()
  + AddValueToSplayTree()
  + AppendValueToLinkedList()
  + CanonicalXMLContent()
  + ClearMagickException()
  + ClipImagePath()
  + CloneCacheMethods()
  + CloneCacheView()
  + CloneImageAttributes()
  + CloneImageProperties()
  + CloneImages()
  + ClutImageChannel()
  + ClutImage()
  + CompareImageLayers()
  + CompositeImageChannel()
  + CompositeLayers()
  + ConcatenateColorComponent()
  + ConfigureFileToStringInfo()
  + ContrastStretchImageChannel()
  + ContrastStretchImage()
  + ConvertHSBToRGB()
  + ConvertHSLToRGB()
  + ConvertHWBToRGB()
  + ConvertRGBToHSB()
  + ConvertRGBToHSL()
  + ConvertRGBToHWB()
  + DefineImageProperty()
  + DefineImageRegistry()
  + DeleteImageAttribute()
  + DeleteImageProfile()
  + DeleteImageProperty()
  + DeleteImageRegistry()
  + DeleteImages()
  + DeleteNodeByValueFromSplayTree()
  + DeleteNodeFromSplayTree()
  + DestroyCacheResources()
  + DestroyFxInfo()
  + DestroyImageProperties()
  + DestroyImageRegistry()
  + DestroyMimeList()
  + DestroyQuantumInfo()
  + DestroyResampleFilter()
  + DestroyStreamInfo()
  + DestroyThresholdMap()
  + DestroyTokenInfo()
  + DestroyXMLTree()
  + DisassociateImageStream()
  + DisposeImages()
  + DistortImage()
  + DrawGradientImage()
  + ExcerptImage()
  + ExtentImage()
  + FileToImage()
  + FormatImageAttributeList()
  + FormatImageAttribute()
  + FormatImagePropertyList()
  + FormatImageProperty()
  + FormatMagickCaption()
  + FormatMagickSize()
  + FormatMagickStringList()
  + FormatMagickTime()
  + FormatStringList()
  + FxEvaluateChannelExpression()
  + FxEvaluateExpression()
  + GaussJordanElimination()
  + GetCacheMethods()
  + GetCacheViewColorspace()
  + GetCacheViewException()
  + GetCacheViewStorageClass()
  + GetCacheVirtualPixelMethod()
  + GetDelegateThreadSupport()
  + GetEnvironmentValue()
  + GetExceptionMessage()
  + GetImageChannelRange()
  + GetImageChannelStatistics()
  + GetImageMask()
  + GetImageProperty()
  + GetImageRange()
  + GetImageRegistry()
  + GetImageTotalInkDensity()
  + GetLastValueInLinkedList()
  + GetLogName()
  + GetImageDecoder()
  + GetImageEncoder()
  + GetMagickQuantumRange()
  + GetMagickResourceLimit()
  + GetMagickToken()
  + GetMimeDescription()
  + GetMimeInfoList()
  + GetMimeInfo()
  + GetMimeList()
  + GetMimeType()
  + GetNextImageAttribute()
  + GetNextImageProperty()
  + GetNextImageRegistry()
  + GetNextKeyInHashmap()
  + GetNextKeyInSplayTree()
  + GetNextValueInHashmap()
  + GetNextValueInLinkedList()
  + GetNextXMLTreeTag()
  + GetOneCacheViewPixel()
  + GetPathComponents()
  + GetQuantumInfo()
  + GetStreamInfoClientData()
  + GetStringInfoDatum()
  + GetStringInfoLength()
  + GetStringInfoPath()
  + GetThresholdMap()
  + GetValueFromHashmap()
  + GetValueFromLinkedList()
  + GetValueFromSplayTree()
  + GetXMLTreeAttribute()
  + GetXMLTreeAttributes()
  + GetXMLTreeChild()
  + GetXMLTreeContent()
  + GetXMLTreeOrdered()
  + GetXMLTreePath()
  + GetXMLTreeProcessingInstructions()
  + GetXMLTreeSibling()
  + GetXMLTreeTag()
  + GravityAdjustGeometry()
  + InjectImageBlob()
  + InsertImageInList()
  + InsertTagIntoXMLTree()
  + InterpolatePixelColor()
  + InterpretImageAttributes()
  + InterpretImageFilename()
  + InterpretImageProperties()
  + InvokeDynamicImageFilter()
  + IsColorSimilar()
  + IsHighDynamicRangeImage()
  + IsHistogramImage()
  + IsImageObject()
  + IsImageSimilar()
  + IsMagickOption()
  + IsMagickTrue()
  + IsOpacitySimilar()
  + LinearStretchImage()
  + ListMagickOptions()
  + ListMimeInfo()
  + ListModuleInfo()
  + ListThresholdMaps()
  + LoadMimeLists()
  + LogMagickEventList()
  + MagickCoreGenesis()
  + MagickCoreTerminus()
  + MagickOpenStream()
  + MontageImageList()
  + NewXMLTree()
  + NewXMLTreeTag()
  + OpenStream()
  + OptimizeImageLayers()
  + OptimizeImageTransparency()
  + OptimizePlusImageLayers()
  + OrderedDitherImageChannel()
  + OrderedPosterizeImageChannel()
  + OrderedPosterizeImage()
  + PaintFloodfillImage()
  + PaintOpaqueImageChannel()
  + ParseAffineGeometry()
  + PolaroidImage()
  + PruneTagFromXMLTree()
  + QueryMagickColorname()
  + RadialBlurImageChannel()
  + ReadBlobDouble()
  + ReadBlobFloat()
  + ReadBlobLongLong()
  + ReadBlobLong()
  + ReadBlobShort()
  + RecolorImage()
  + RegisterDNGImage()
  + RegisterEXRImage()
  + RegisterINFOImage()
  + RegisterIPLImage()
  + RegisterJP2Image()
  + RegisterTHUMBNAILImage()
  + RemoveDuplicateLayers()
  + RemoveImageProperty()
  + RemoveImageRegistry()
  + RemoveZeroDelayLayers()
  + ResampleImage()
  + ResamplePixelColor()
  + ResetImageAttributeIterator()
  + ResetImagePage()
  + ResetImagePropertyIterator()
  + ResetImageRegistryIterator()
  + ScaleResampleFilter()
  + SeedRandomReservoir()
  + SeparateImages()
  + SepiaToneImage()
  + SetCacheMethods()
  + SetCacheViewStorageClass()
  + SetCacheViewVirtualPixelMethod()
  + SetCacheVirtualPixelMethod()
  + SetImageInfoBlob()
  + SetImageInfoFile()
  + SetImageMask()
  + SetImage()
  + SetImageProperty()
  + SetImageRegistry()
  + SetImageStorageClass()
  + SetLogName()
  + SetResampleFilterVirtualPixelMethod()
  + SetStreamInfoClientData()
  + SetStreamInfoMap()
  + SetStreamInfoStorageType()
  + SetStringInfoPath()
  + SetXMLTreeAttribute()
  + SetXMLTreeContent()
  + SigmoidalContrastImageChannel()
  + SigmoidalContrastImage()
  + SketchImage()
  + StreamImage()
  + StringToken()
  + SyncImageOptions()
  + SyncImageProfiles()
  + ThrowMagickExceptionList()
  + TransposeImage()
  + TransverseImage()
  + UniqueImageColors()
  + UnregisterDNGImage()
  + UnregisterEXRImage()
  + UnregisterINFOImage()
  + UnregisterIPLImage()
  + UnregisterJP2Image()
  + UnregisterTHUMBNAILImage()
  + VignetteImage()
  + WriteBlobFloat()
  + WriteBlobLong()
  + WriteBlobShort()
  + XAnimateBackgroundImage()
  + XAnimateImages()
  + XDisplayBackgroundImage()
  + XDisplayImage()
  + XMLTreeInfoToXML()

* Removed API functions:
  + AcquireCacheView()
  + AcquireTemporarySymlink()
  + AddValueToSplayTree()
  + AnalyzeImage()
  + AnimateImageCommand()
  + AppendValueToLinkedList()
  + ClipPathImage()
  + ClonePixelCacheMethods()
  + CompareImageCommand()
  + CompositeImageCommand()
  + ConjureImageCommand()
  + Contrast()
  + ConvertImageCommand()
  + DeleteImageList()
  + DisplayImageCommand()
  + ExecuteModuleProcess()
  + FormatSize()
  + GetValueFromLinkedList()
  + GetValueFromHashmap()
  + GetImageInfoAttribute()
  + GetLastValueInLinkedList()
  + GetLocaleMonitorMessage()
  + GetLocaleValue()
  + GetMagickDecoder()
  + GetMagickEncoder()
  + GetNextValueInLinkedList()
  + GetNextKeyInHashmap()
  + GetValueFromSplayTree()
  + GetMagickToken()
  + HSBTransform()
  + HSLTransform()
  + Hull()
  + HWBTransform()
  + IdentifyImageCommand()
  + ImportImageCommand()
  + InsertImageInList()
  + InterpolateColor()
  + InvokePostscriptDelegate()
  + IsTrue()
  + JPEGEncodeImage()
  + LoadWPG2Flags()
  + MagickIncarnate()
  + ModulateHSB()
  + ModulateHSL()
  + ModulateHWB()
  + MogrifyImageCommand()
  + MogrifyImageInfo()
  + MogrifyImageList()
  + MogrifyImage()
  + MogrifyImages()
  + MontageImageCommand()
  + RegisterDOTImage()
  + SetPixelCacheMethods()
  + SyncBlob()
  + SyncCache()
  + TransformHSB()
  + TransformHSL()
  + TransformHWB()
  + UnregisterDOTImage()
  + Upsample()

* Changed API functions:
  + AcquireCacheNexus(), new function argument
  + GetCacheViewPixels(), new function arguments 
  + ZLIBEncodeImage(), function argument removed 
  + SigmoidalContrastImage(), function arguments removed and changed
  + GlobExpression(), new function argument
  + GetExecutionPath(), new function argument