Adobe recently released the Lightroom SDK 10.0. There aren't many changes from the LR SDK 9.3. Adobe long ago stopped putting any significant effort into the SDK, including documenting what's changed. So here are the results of my semi-automated change detection:
Readme.txt
Only cosmetic changes
The Lightroom SDK Guide
Only cosmetic changes
API Reference
LrApplicationView
zoomToOneToOne () -- new function
zoomIn(), zoomOut() -- documentation changed slightly
zoomInSome(), zoomOutSome() -- marked as "deprecated"
LrDevelopController
ColorGradeShadowLum, ColorGradeHighlightLum, ColorGradeMidtoneHue,
ColorGradeMidtoneSat, ColorGradeMidtoneLum, ColorGradeGlobalHue,
ColorGradeGlobalSat, ColorGradeGlobalLum, ColorGradeBlending -- new params for getValue/setValue
getActiveColorGradingView(), setActiveColorGradingView () -- new functions
revealPanel(), revealPanelIfVisible () -- the panel ID "colorGradingPanel" replaces "splitToningPanel", an incompatible change
Undocumented Changes to the API
LrAnalytics -- more functions added to this undocumented module used for internal performance reporting
LrPhoto -- obsolete, unused Develop settings for getDevelopSettings() deleted: LensProfileChromaticAberrationScale, ToneCurveBlue, ToneCurveGreen,
ToneCurveRed, ToneMapStrength
LrDevelopController
obsolete, unused params for getValue/setValue deleted: OutputContrast, OutputVibrance, AutoBrightness, AutoContrast, AutoExposure,
AutoGrayscaleMix, AutoShadows, AutoTone, CustomTemperature, CustomTint,
LensProfileChromaticAberrationScale, OutputContrast, OutputVibrance,
ToneCurve, ToneCurveBlue, ToneCurveGreen, ToneCurveRed, ToneMapStrength
customIncrementalTemperature, customIncrementalTint -- added params for getValue/setValue; they appear the same as IncrementalTemperature/IncrementalTint and were probably added by mistake
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