Changes
- Improve SPL Token developer experience
- Harden signature verification input validation
- Activate new fork choice rules for mainnet-beta at slot 26,752,000 (near the end of epoch 61)
- Be more strict about which authorities can withdraw from stake accounts with an active lockup *
* NOTE this change requires a client update. Be sure your CLI tools are v1.2.16 or newer everywhere you intend to interact with stake accounts