Unity have just released a rather large patch for Unity 5.5.1p1. Loaded with fixes, there are also a couple of improvements to the Android gradle builds as well as a couple new graphics API in the Mesh class. Complete patch details from the release notes:
Android: Gradle export now supports custom template
Android: Gradle export troubleshooting added
Graphics: Added new APIs: Mesh.GetIndexStart and Mesh.GetIndexCount.
Tizen: Added a button to the deployment target window to refresh the target list.
Tizen: Remove the Tizen 2.3 minimum OS option. 2.4 is now the only accepted OS version. Users must update their devices to Tizen OS 2.4.
(852307) - Android/IL2CPP: Prevent a crash which can occur with the use of OnAudioFilterRead callbacks on krait CPUs.
(none) - Android/Metro: Fixed the issues preventing the Application.Unload API from functioning correctly.
(856650) - Android: Gradle export should now work with SDK version > 6.0.
(854535 ) - Android: Gradle export -Fixed colliding package name for unity-android-resources
(869582) - Animation: Fixed a crash when setting Animator.updateMode when no AnimatorController is set.
(860366) - Animation: Fixed edit key overriding key frames in curve editor.
(862004) - Asset Bundles: Fixws intermittent freeze that could occur when calling AssetBundle.LoadAssetAsync multiple times in a single frame.
(871730) - Cache Server: Fixed the custom port missing for the remote option.
(none ) - Editor: Fixed light probe rendering in LookDev HDRIs. Previously it could go wrong depending on the lighting panel parameters set for the project.
(862005) - Graphics: Fixed crash in occlusion culling when loading multiple scenes.
(860775 ) - HoloLens: Fixed a crash that occurs on device when downloading files with WWW.
(867606) - IL2CPP: Allow the build to succeed when the .NET 4 TargetFrameworkAttribute attribute is used in an assembly.
(863806) - IL2CPP: Correct an error in UnusedBytecodeStripper2 related to UnityEngine.RenderTexture that can occur during some project builds.
(828288) - iOS: Fixed an issue where the ReplayKit API might be reported as available on unsupported devices
(796649) - iOS: Fixed orientation requests from the app getting out of sync with iOS orientation.
(829753) - Kernel: Json serialisation now supports correct parsing of NaN and +/-Inf.
(none ) - Lighting: Fixed baked light map visualisation shading mode in the Editor.
(861293) - LineRenderer: fixed gaps when values are repeated
(864043) - LineRenderer: Fixed issue where setting endColor failed if using different number of color/alpha keys
(847798 ) - Mono: Correct an invalid C# compiler error with generic types in compiler generated code (like lambdas and enumerators). The error from the C# compiler often includes this text: "There is no boxing or type parameter conversion from..."
(836770) - Networking: Fixed issue where unspawn handler was not properly invoked during object cleanup (like in NetworkManager.StopClient())
(864122) - Particles: Fixed "TLS ALLOCATOR ALLOC_TEMP_THREAD" error messages
(862777) - Particles: Fixed crash in LightsModule when destroying systems
(862897) - Particles: Fixed crash in ParticleSystem.Emit()
(856842) - Particles: Fixed issue where distance-based emission was not working
(862352) - Particles: Fixed issue where particle bounding boxes could become corrupted, resulting in "Invalid AABB" messages
(861347, 863060 ) - Particles: Fixed issue where sub-emitters were causing memory leaks
(862976) - Particles: Fixed issue where switching Render Mode could cause rendering artifacts
(868648) - Particles: Fixed rare crash when using the Trail Renderer and Multithreaded Rendering is enabled.
(862921) - Particles: Fixed rotation bug with mesh particles
(864208) - Particles: Fixed TrailModule crash when enabling trails and using ParticleSystem.SetParticles
(861409](https://issuetracker.unity3d.com/product/unity/issues/guid/861409/)) - Particles: Stretched billboards could apply scale twice if using Speed Scale
(859436) - Particles: Texture Animation could skip frames and display invalid data
(none ) - Physics 2D: Optimize the CapsuleCollider2D component intersection tests for speed and accuracy.
(none ) - Purchasing: Fixed a bug where a duplicate transaction could fail without calling the failure callback.
(none ) - Scripting: Added the following non-allocating accessors to Mesh. These accessors write into a user-specified List. The accessors are GetBindposes, GetBoneWeights, GetColors, GetIndices, GetNormals, GetTangents, GetTriangles, and GetVertices.
(856507) - Shaders: Fixed shader compilation error when compiling certain surface shaders using WorldNormalVector from INTERNAL_DATA e.g. shadow pass variations.
(810571) - Splash Screen: Fixed an issue where the splash could be truncated by a first scene taking a long time to load
(872286 ) - Tizen: Change the minimum API level to Tizen 2.4 in PlayerSettings.
(869995 ) - Tizen: Fix a NULL referencing while exiting the game.
(834785) - Tizen: Improve error when failing to discover a deployment target.
(none ) - Tizen: Improvements to emulator deployment.
(none ) - Tizen: SystemInfo.processorFrequency now returns proper values.
(869964) - TrailRenderer: Fixed visual artifacts when manually enabled during Play mode
(861828) - UnityWebRequest: fix proxy support, so that debuggers like Fiddler work.
As always, the patch is available for download here.