This is the release candidate for the first supported release of the 2.5 series. It contains several minor fixes and enhancements since beta-2, but should not be a break in backwards compatibility for ABI/linkage. Please see the CHANGES.md file for details (any changes since the first beta will be identified as "2.5.3.2-rc1".) You are encouraged to try to build and use this beta to help identify anything that should be fixed before the release.
Our current plan is that on October 1 (or very shortly thereafter), to remove the RC designation, and have that become the supported production release family, with 2.4 becoming the obsolete branch with gradually diminishing support in the coming months.