Problem
You are unable to deploy packages on a environment and an error appears.
”This package was created on a version that is no longer supported on this target Environment. In order to deploy this solution to this target environment, upgrade the source environment to align with the same version as the target and repackage the solution. Then reattempt deploying this package”
Solution
After installing a Cumulative Update (CU) or Fix Pack (FP), any time you use the Reconfigure, Update, or Modify option in the Setup Manager to make changes to your installation, you must reinstall the same or latest CU and FP.
Please refer to the following article: https://help.nintex.com/en-US/k2five/icg/5.6/Content/Maintain/ReconfigEnv.htm