Use the actual target client as the final test. A simulator checks useful parts of an addon, but it cannot certify every API or combat condition.
Will my existing Classic or Retail addon work?
Treat each addon separately. Its dependencies, API calls, saved-data format, and behavior matter more than the label on the download. Look for a release and testing notes from its author for the client you use.
For a small personal addon, write down the behavior you want to preserve before rebuilding it. That might be a movable label or a notebook, rather than every feature accumulated in the original. Do not assume an AI rewrite can recreate information the game does not expose.
Start with the manifest and dependencies
The TOC manifest tells the client which files to load and contains interface metadata. Check the intended client build, the listed filenames, and any dependency requirements. Files must be present in the expected folder.
Changing only the interface number is not a port. It can change whether the client flags the addon as out of date, but it does not restore a removed function or update a changed return value.
Displayable information is not always inspectable
Blizzard’s published Midnight guidance distinguishes displaying protected combat information from allowing addon code to analyze it. A visible cooldown on a game widget does not by itself establish that Lua can compare its value or use it in a condition.
For WoW Forever, check the actual API and restrictions in the client you are targeting. Ask the builder for a clear unavailable state or a supported display fallback. A preview with simulated, ordinary values is not evidence that restricted values can be inspected in game.
Know what the preview proves
ForeverMods runs the generated Lua in wow-ui-sim. Use it to inspect the output and exercise supported clicks, dragging, commands, and simulated events. An empty preview can also be legitimate: some addons act only on a command or event.
The simulator is not the game client. A successful preview does not prove server communication, every game API, combat permissions, saved-data behavior across real logins, or correctness on every character.
Keep a short compatibility checklist
Test a single addon version with a specific client build and record the outcome. This makes a future patch failure easier to diagnose.
- Enable the addon with only its required dependencies.
- Test it on the intended class and on a character without the relevant ability.
- Exercise the main interaction, then reload and change zones.
- For combat-related UI, test both outside and inside combat.
- Verify saved settings and the behavior when data is unavailable.
- Record exact errors and retest after client updates.