OptiFine 1.9.0_HD_U_B2_pre
 - updated Forge compatibility, not backwards compatible
 - fixed Natural Textures for snow layer sides
 - added Better Grass for grass paths, snowy podzol and snowy mycelium
 - added Better Grass configuration (per block, textures)
 - fixed ForgeHooksClient.onDrawBlockHighlight
 - fixed off hand rendering with shaders
 - added shader uniforms "heldItemId2" and "heldBlockLightValue2" 
 - added shader option Old Hand Light for backward compatibility with shaders packs supporting only main hand light
 - added option "oldHandLight=true|false" in "shaders.properties"
 - compatible with Forge #1863
 (07.04.2016)
 
OptiFine 1.9.0_HD_U_B1
 - fixed memory usage with AF and AA
 - fixed single-core chunk loading
 - enabled simple spectral effect when Fast Render, Antialiasing or Shaders are active
 - fixed chunk loading when changing dimensions 
 - removed all Mojang content from final JAR  
 - added support for class patches
 - updated to Minecraft 1.9
 - compatible with Forge #1797
 (26.03.2016)