We are about to upgrade the Nintex 2010 Workflow version on each farm (Prod, Test, Dev). We have development occurring on the Dev environment continuously. The plan to upgrade the farms is to start with the development farm, run some tests on the workflows and come up with a strategy to upgrade the test and prod farms based on the results from the tests.
During the validation time period in development (which now has the upgraded version), development on new workflows will continue to occur.
Will we need to cease promoting workflows through the environments until the upgrade process has been executed on the remaining two farms? If we were to promote workflows to the test and prod farms I assume we would encounter issues, what would be their cause and is there a possibility of mitigating these?
e.g. I create a workflow with a flexitask in the upgraded farm. I specify a BCC recipient. Will this workflow be able to be promoted to a farm running a previous version which does not have the BCC functionality for Flexitasks?
in most cases you will be able to export / import workflows even if the installed version is not exactly the same as in the development farm. But as you already guessed it might cause problems if you use new features only available in the newest version.
If you need to prevent users from copying workflows during the evaluation period you could restrict their permissions of publishing workflows by removing them from the workflow designers group in site settings -> Nintex Workflows -> Allowed Workflow designers.
Would that be an option?