It sounds like you may have missed a step in the installation. Did you do what is directed in https://webwork.maa.org/wiki/Installation_Manual_for_2.18_on_Ubuntu#Install_Dependencies?
To check this run "perl -MMojo::SQLite\ 9999". That should return
Mojo::SQLite version 9999 required--this is only version 3.005.
BEGIN failed--compilation aborted.
Hi Glenn, thank you for the reply. Yep, that's exactly the issue.
I followed the section "Set Up the Webwork2 Job Queue" in the installation file and downgraded MMojo::SQLite to version 3.002
Then LTI grade update works!
When we upgraded to 2.18, I probably just read the upgrade instructions that's most likely why I missed that session.
Yeah, the last bullet item in the upgrade instructions just gives the link to the section in the installation instructions and says the step is optional. I can see how it is easy to miss.