The server/DC version of the Reminders app has been in the Atlassian Marketplace for years. There are some differences between the Cloud and Server/DC versions of the app. Some of the limitations of the Cloud version are caused by the limitations of Atlassian’s Forge platform, and some are not implemented yet.
The following are the main differences you should be aware of when migrating from the server/DC version of this app to the Cloud version.
Limitations of Cloud Version
You can't send reminders to “project roles” and direct e-mail addresses in the cloud version of the app.
There are no JQLs for finding issues with reminders. Currently, this is not possible with the Forge Platform.
Advantages of Cloud Version
You can send reminders to Slack workspaces in the Cloud version. This feature is not available for Server/DC versions.