Version 0.6.2 has a bug that can be exploited for remote code execution. This is an emergency release, and 0.6.4 will be released in a couple of days with cleanup originally intended for 0.6.3, and full release notes. Everyone who uses 0.6.2 should upgrade (or, if upgrade is not possible, downgrade).
Apart from the emergency fix, this release contains a new network subsystem which requires less resources (CPU and memory) and the Dandelion++ protocol extension for enhanced privacy.
Windows and OSX binaries follow soon.