Curve rolls out a new version: v0.3. It has multiple logging changes, some tweaks to the algorithm (it should give a slightly higher profit), and others. Every feature makes its own commit.
In order to migrate, withdraw everything (100 %) at withdraw from old contract page, and deposit at the deposit page.
Check out the video of the process.
Remember, this is still an alpha software - more migrations, or more changes may occur, smart contract audit and formal verification are still to happen.