Keepass Passwordsafe - Introduction to V 2.35 and KDBX 4
KeePass 2.35 introduces version 4 of the KDBX file format. This new format features both improvements and new capabilities. These are outlined in the following sections.
There are a few changes to the inner XML format since KDBX 3.1 (the HeaderHash meta element is obsolete now, see Improved Header Authentication; new CustomData element for entries and groups; new SettingsChanged element). The wrapping, binary format heavily changes. Furthermore, the order of encryption and data authentication changes.
Migration Phase. As not all major KeePass ports have finished adding support for KDBX 4 yet, for now KeePass 2.35 saves databases in this new format only when at least one of the following conditions is fulfilled:
- AES-KDF is not selected as key derivation function (KDBX 3.1 only supports AES-KDF; any other key derivation function, like for instance Argon2, requires KDBX 4).
- A plugin requests to store custom header data in the KDBX file.
- A plugin requests to store custom data in an entry or a group.
As soon as all major KeePass ports support KDBX 4, KeePass will always save in this format.
Martin Brinkmann, ghacks, has an article about the new upcoming version: