since some new options to bitcoind are considered more for debugging and tinkering than for end users, they did not make it into the release notes. Therefore, here is a more complete such list:
- -upgradewallet: new wallets in 0.6.0 are created in the latest format, but old wallets are left untouched in order for them to remain compatible with external tools. -upgradewallet forces the wallet to upgrade to the latest format
- -upgradewallet=<n>: allow (but do not force) an automatic upgrade to a wallet that is still compatible with client version n (for example -upgradewallet=50000 will make sure the wallet remains compatible with 0.5.0). One exception is when the user takes an explicit action that implies a wallet upgrade (encrypting it, for example), and the condition specified by -upgradewallet=N is not satisfiable. In that case, the wallet will still be upgraded to the latest format anyway. You can also use this option to create a new wallet that is compatible with older versions.
- -checkblocks=<n>: In addition to -checkblocks (which verifies the entire chain), or no argument at all (which verifies the last 2500 blocks), you can now specify how many blocks the to check. For example, -checkblocks=10 will only verify the last 10 blocks. The minimum is 1, specifying 0 will cause a check of the entire chain
- -checklevel=<n>: specify how thorough the inital block validation algorithm is. The default is 1, and corresponds to the level of checking older versions did. In 0.6.0, any number between 0 and 6 is accepted, each significantly slower than the previous one. Checking the entire chain at level 6 will take at least 5 minutes if the blockchain is already loaded into the OS cache entirely.
- -dbcache=<n>: Specify how many megabytes of memory to use for internal caching. The default in 0.6.0 is 25, and higher numbers will not gain you much more speed probably. Higher numbers mean slower startup and shutdown, though.