The Resourcepack has been properly updated to 1.15. @oldbooksmell delivered exceptional and invaluable work cleaning up all of my sloppy errors and bad texture updates from 1.13, and did all of the heavy lifting in the base texture pack. I then worked on what they delivered, and made some modifications while updating some textures that were left unused since 1.13. Now we might have the least buggy/broken texturepack we've ever had, thanks to oldbooksmell, and a good middle ground between Survival requests for rollbacks on textures and roleplay texture needs.
Anticipating the release of 1.15 during the next restart, players should expect some hours downtime as the server update is deployed. In the meantime, 1.14 clients (should) still be able to connect, but it may take a while for the server to get back up again. It should be back before prime time, for sure.
The texture pack can be directly downloaded from: http://files.massivecraft.team/resourcepack/MassiveCraft-1.15.zip
Just drop this zip file (without unpacking it) into your resourcepacks folder in your Minecraft base folder.
Enjoy, and remember to shoot oldbooksmell an appreciation message if you want to thank her for fixing the annoying bugs!