Besides the User Group Picker PRO™ app itself, there are also two dependencies, two complementary apps that are installed with it:

• SIL Engine™ – a library having countless utility routines, but most importantly, it contains a SIL™ language parser. 
• warden – licensing support for several of our apps
  
  

Installing via Atlassian Universal Plugin Manager

If you are connected to the Atlassian Marketplace website from your Jira administration console, you can install our apps directly from the Marketplace. For  
For more information, see Installing add-ons and Universal Plugin Manager pages.

1. Log into your Jira as Admin.
2. In the cog wheel menu, go to Add-ons.
3. In the search field of the Find new add-ons section, search for "User Group Picker PRO™".

...

User Group Picker PRO™ is only compatible starting with Jira 7v7.0.0 and higher; JDK version should be at level 8.

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1. Uninstall warden.
2. Uninstall the SIL Engine™.
3. Uninstall UGP Pro™the User Group Picker PRO™.

4. Install a the version of UGP Pro™ that the User Group Picker PRO™ that is compatible with your Jira version.
   SIL Engine™ and warden should now have the right versions as well.

5. Check any dependent apps, such as Power Scripts for Jira™ or Jira™, Power Actions™, etc. These Note that these apps must be re-enabled manually manually.