You probably have more than one version of commons-io-X.X.X.jar in your application. Check your userlib and vendorlib and make sure you only have one copy. If there is more than one, keep the version in vendorlib. If not in vendorlib, keep the highest version in userlib. Finally, clean your deployment directory before rebuilding incase an older version has been cached there.
Good luck!
I'm experiencing the exact same issue (with Community Commons 10.4.0 on Mendix 10.12.19), with only commons-io-2.18.0.jar installed (in vendorlib folder, nothing in userlib folder).
Also cleaning deployment directory did not help.
Any other suggestions or experiences anyone?
See the answers from Chris
https://community.mendix.com/link/spaces/marketplace/questions/143378https://community.mendix.com/link/spaces/marketplace/questions/143378