They are promoting "The 28th International Rexx Language Symposium will be on April 10th - 12th, 2017, The Netherlands."
It can be interesting for the OS/2 community to do some presence there.
In or near the home town of both the RexxLA President, Amsterdam, and near whatever's left of Mensys.
RexxLA, with its Open Object Rexx, may be the wrong bet. If you would want to talk to the members about about our Object Rexx, for example to strategically point out that we may be the largest non-mainframe community of Rexx users by far, then there is actually no "topic area of particular interest" which would cover the generic topic of your OS/2 presentation. After such a presentation I'd expect a few nice words and exchanged OS/2 memories, but no meaningful help. They already have got what they wanted, and they have "moved on".
And, again, I'm not sure what the added value of Object Rexx is, in our world of Classic Rexx apps. I'm using the interpreter, despite of a few problems like running out of shared memory or syntax-checking broken legacy software, but only because of the 3 parameters of the Date() built-in function. Regina should support this too. Most object-oriented code will be used to produce a GUI, but we already have such an environment. VisPro/REXX, VX-REXX, and so on. An OO GUI, on top of any Classic Rexx interpreter of the OS. Or, in other words, which existing software requires an Open Object Rexx for OS/2?
If IBM requires a RexxLA to release our source code: fine. Otherwise RexxLA isn't that interested in, for example, Object Rexx/2. RexxLA is n't always excluding OS/2, but a topic like "Novel, clever, or interesting problem solutions using ooRexx or Classic Rexx" does. There is only one Object Rexx interpreter: theirs. No Object Rexx/2, no generic "Object Rexx", and even no IBM Object Rexx for Windows with its IDE. A functional language association should use the name of the language instead of the name of a brand. Their own brand, in this case. RexxLA is not an inclusive association.
I guess I'll survive listening to people using ooRexx and Java to populate their Excel spreadsheets for three days, but it may be more useful to become a member which represents the OS/2 community. It's a small world, so the vote ($24/year) will count. The ooRexx symposium costs $30 (3 days), excluding costs.