Any realistic way to license ColdFusion 2021 for a short transition?

Ask Adobe sales or support directly whether a current purchase includes downgrade rights to ColdFusion 2021, and get the answer in writing before buying. Availability of an installer and permission to use it are separate questions, so I would not assume a newer subscription automatically provides an older-version key.

For a temporary bridge, a managed ColdFusion host may be simpler than sourcing a standalone license and maintaining the server yourself. Ask providers whether they can run the exact version your app needs, what license covers it, and whether they can support your dependencies. Confirm the term and migration or export options too, so the temporary setup does not become another long-term dependency.

If the app is already working under Developer edition, check whether its usage fits that edition's limits before treating it as a production option. Developer licensing is not a general substitute for a production license. For a short production bridge, get written guidance from Adobe or a qualified hosting provider rather than relying on an informal workaround.

Another possibility is testing whether the app can run on Lucee, but I would treat that as a compatibility investigation, not a quick license fix. Older ColdFusion code can depend on specific engine behavior, extensions, or server configuration. Inventory those dependencies first and run a representative test before counting on a switch.