The senhasegura backup encryption process is directly linked to the master key applied to the system. When a backup file is created, its encryption is derived from this master key.
If there is a new master key ceremony that generates new keys, you will not be able to access a backup that belonged to the old key unless there are still required parts compatible with the previous ceremony.
However, it is not necessary to resort to old backups as senhasegura backs up credentials daily. These backups are updated with each change in credentials, whether done manually or through automatic password change. Therefore, if you need to open a password backup, you should always opt for the most current one.