Problem Definition

The embedded database in Confluence is ONLY supported during evaluation per the above linked documentation.

The embedded H2 database is only supported while you are evaluating Confluence. You must migrate to a supported external database before using Confluence as a production system.

However, it may not be clear from this that the embedded database is also not supported when upgrading the system. This can cause many issues such as the one from this forum post:

http://h2-database.66688.n3.nabble.com/TimeNanos-out-of-range-when-using-different-version-of-jar-No-check-when-DB-upgraded-td4033636.html

In general, the solution for this is to migrate to a supported database.

Suggested Solution

Clarify on the documentation that the H2 database is only supported within evaluation, including when upgrading or migrating a Confluence instance.