This application uses Payara 6.2021.1 Alpha 4. I used a Maven archetype for Jakarta EE 9.1. I think it will work with Payara 6.2021.1 but perhaps Payara changed something between the alpha 4 and the final version of 6.2022.1?
Jakarta EE 9.1 works with Payara 6.2021.1 Alpha 1 while Payara 6.2022.1. Alpha 4 and the final version use Jakarta EE 10. Nothing fundamental has changed between Payara 6.2022.1 Alpha 4 and the final version.
First, I would advise you to test on Alpha 4 and see if it works. I would also recommend that you upgrade to Jakarta EE 10 so that you do not see any unwanted side effects.
I was surprised to read that the final version version is only compatible with Jakarta EE 10 and not with Jakarta EE 9.1.
I have already tested the Alpha4 version with my Jakarta EE 9.1 application and everything I have tested seemed to work fine. Obviously I didn’t test everything and I would like to know why Payara says that the final version is not compatible with Jakarta EE 9.1.
I plan to upgrade to Jakarta EE10 but the development tools are not yet well adapted.