@gdeer81 i followed your suggestion to exclude guava from datomic and my deploy to heroku went cleanly. Thanks for the push. if you dont mind could you explain at a high level your thought process for diagnosing the problem? I saw from the stack trace it was trying to call a method that didn’t exist. And i believe i would have been able to figure out which library it belonged to (guava). From their do you just use the dependency tree (lein deps :tree) to see who is conflicting on that library?

I cheated and used google, someone had the exact same issue about six months ago so it was at the top of the search results

hmm yes, i think i recall the one. Next time ill have more faith in my google search results.