We have lots of free Unity goodies available on GitHub so be sure to give them a look!

Read the release notes before updating any plugin! Important information may be present.
If you are seeing "P31MonoBridge" errors when doing IL2CPP builds that is a good sign you didn't read the release notes before updating! Mono doesn't exist in IL2CPP builds so you must delete the P31MonoBridge file and make sure all plugins are up to date.
Unity 5 has a bug where it will duplicate files when importing a unitypackage. When Unity duplicates a file they will start appening digits after the name (for example P31RestKit_1.dll, P31RestKit_2.dll, etc). You will need to manually delete these duplicates until Unity fixes the issue.
Unity 5 shipped with a bug with the way they link the GameKit.framework. To fix the issue do the following: 1. open the Unity Xcode trampoline (located in the Unity install folder/Unity.app/Contents/PlaybackEngines/iossupport/Trampoline), 2. open the Xcode project settings -> Build Settings -> Link Binary With Library section (as in this image), 3. Click the '+' button and add the GameKit.framework. All builds you make after doing that will properly link the GameKit.framework.

Another way to remedy the issue is to use our new build system (which is currently an opt-in beta. See the below alert for details). The new build system update that went out the day Unity 5 was released has a hack that works around the framework linking issue. As always, you can fetch it via the Tools -> prime[31] -> Update prime[31] tools menu item.
Our new build system will be going live for all plugins in a couple weeks. You can opt-in to using the new build system very easily. Simply move any plugin folders from the Editor/PLUGIN_NAME folder to the Editor/Prime31/PLUGIN_NAME folder. See this 7 second video for an example. You can toggle the build system logging via the Tools -> prime[31] menu item (hint: very handy for reporting bugs if you find them!).
Prepare for the future! All updates from this day forward will now put all plugins into the Prime31 namespace. As a result of the change, any files you have that access the plugin code will need to have a "using Prime31;" statement added at the top of the file.