So please help look for last-minute showstopper issues:
https://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.6.0/test/
The major changes from release candidate 4:
- Much faster writing of blkindex.dat during initial blockchain download (by modifying the default bdb environment cache settings)
- A new policy for wallet.dat upgrades: use the old format unless the user either uses a feature that requires an upgrade (encrypts the wallet) or explicitly requests that the wallet be upgraded using the new -upgradewallet option. New wallets will use new features (for 0.6, the only new wallet feature is compressed public keys).
- bugfix introduced in rc4 for an assertion failure that could occur during blockchain reorganizations
- New code for managing the addr.dat file that prevents an attacker from filling it with bogus entries.