A heads up: I hit an issue on eZ Platform v1.13.0 upgrade that I could no log in. On the first time I could log in, but the next time it no longer worked.
This was due to changes in password hashing in v1.12 and v1.13. The first version added longer password hashes and v1.13 added automatic updates. If you don’t follow the upgrade procedure and apply the DB update that came with v1.12 then the hashes will be stored incorrectly.
More information in JIRA ticket “Corrupt password when upgrading to eZ Platform 1.13 from earlier versions without DB update”: https://jira.ez.no/browse/EZP-28692