(Only 1.12.2) If you experience a crash along the lines of any of these errors specifically referencing Mystical Lib, please try the following steps before filing an issue report:

• Update Mystical Lib. The latest version as of posting this is 1.7.0.
• If you have Mystical World installed, please ensure this is up-to-date. The most recent version as of posting this is 1.8.4
• If you have Roots installed, please ensure Mystical World is up-to-date, and please ensure that Roots is up to date. The most recent version as of posting this is: 3.0.26.

This error occurs because the version of MysticalLib that you have installed is too old for the version of Mystical World or Roots. It can also occur if you have old versions of Mystical World or Roots and the latest version of Mystical Lib.

• If you don't have Roots or Mystical World installed and are getting issues with Blockcraftery, please file an issue.
• If you are having issues with Crissaegrim, please be aware that the current version of MysticalLib doesn't support Crissaegrim. This is a mistake, but as I do not have access to the Crissaegrim source code I'm not able to resolve the issue at the minute. I will endeavour to do so in the future.

What version of MysticalLib do you recommend for Crissaegrim-1.12.2-1.0.0.jar?

Thanks

I just tried the last version of mysticallib-1.12.2-1.0.0.jar (Oct 31 2018) released just before Crissaegrim-1.12.2-1.0.0.jar, and it's working. Would recommend that you put this as a big bold warning on the top of the Crissaegrim mod page, and possibly a direct link to the older version of the mysticallib dependency.

I tested this with MC 1.12.2, Forge 14.23.5.2847, and OptiFine-1.12.2_HD_U_E3. WORKS with both SP and Server/Client

I unfortunately do not have any access to the Crissaegrim mod or modpage, sorry.