Update to v 1.12.8

The Vernalis plugins have just been updated to v 1.12.8 in the Nightly and Stable 3.5 builds.

This latest update:

Additionally, this brings the nightly build back into line with the stable v3.5 build. (See Update to v 1.12.7 for details of other changes made since the previous nightly build version was released in September 2018)