This version is primarily to fix the issue that people were having with 502 errors when authenticating.
This version should only have issues when minecraft.net is actually down. Sometimes it was returning errors when there were none, more so in the last 12 hours.
There's also a minor fix to the Direct Connect feature where the "Go" button is highlighted when you select the input box, so it makes it easier to paste and press enter. Direct Connections now also count as your "Resume" session so if you Direct Connect and then quit, you can Resume back to the server you were just on.
No "fix" for the jumping bug yet... I'll be looking at it next, this release was just to get the 502 fix out ASAP.