Hi @Peter,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, your question is whether Exchange Server Subscription Edition supports Edge Transport Server. There is no dedicated ‘Edge Transport Server Subscription Edition’ as a product form.
1.Exchange Server SE RTM will support all the same server roles, editions, and prerequisites as Exchange Server 2019. Source: Upgrading your organization from current versions to Exchange Server SE | Microsoft Community Hub
- To allow for rapid adoption and deployment, the RTM release of Exchange Server SE will be code equivalent to (e.g., the same exact code as) Exchange Server 2019 CU15, except for the following changes:
- The License agreement, an RTF file shown only in the GUI version of Setup, will be updated.
- The name will change from Microsoft Exchange Server 2019 to Microsoft Exchange Server Subscription Edition.
- The build and version number will be updated.
There are no changes related to Edge Transport Server in these changes , source: Exchange Server Roadmap Update | Microsoft Community Hub
In summary, Edge Transport Server for Exchange Server 2019 is able to coexist and work with Exchange Server Subscription Edition, provided that compatibility and configuration requirements are met.
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Thank you for your support and understanding.