I am currently looking into the feasibility of moving an application running on ColdFusion to Lucee. The current release version as far as I can see is 18.104.22.168. As far as compatibility goes what version of ColdFusion does this most represent. I realise there will be things that are not supported in Lucee anyway.
I can then look at which version of our code base to test within a Lucee environment.
I would recommend testing against your latest ACF code base, off the top of my head, some of the newer ACF2018 compatible features are only in the 5.3.x versions.
Depending on your schedule, testing against the latest, i.e 22.214.171.124-SNAPSHOT means you will be testing with all the latest fixes, you can expect a 5.3.2 RC soonish I guess and then a stable release to be released about month after the RC
Testing against any older versions of Lucee may mean you encounter and waste time with problems that have already been solved.
Perfect I will take a look at 126.96.36.199-SNAPSHOT