I don't see anything about being able to upgrade from 4.1.5a. Can someone please confirm if there is an issue with 4.1.5a or was it left out by mistake in the release notes?

Upgrading to version 4.2.1 is supported only from versions 4.0.19, 4.0.25, 4.0.27, 4.1.1d, 4.1.3, 4.1.3a, 4.1.3b, 4.1.5b, 4.1.5c, 4.1.5d, 4.1.5e, 4.1.5f, and 4.1.7.

Thanks,

John