Notes IDs
The minimum key size for newly registered Notes IDs was increased to 1024 bits in V11.0.1 and the default key size for newly registered Notes IDs was increased to 2048 bits in V12.0.
Existing IDs with smaller keys that were created by older versions of Notes and Domino can still be used with V12, but for improved security we recommend using the User Key Rollover and Server Key Rollover features to upgrade existing ID files with smaller keys to 2048 bits.