I worked in an IBM mainframe shop as my first job. The COBOL devs for the most part did not participate in programming/tech communities. It was a 9-5 job and they didn't think about it otherwise. Maybe they would have a subscription to Datamation magazine or something like that but I doubt it.

But keep in mind there was no internet, no podcasts, no youtube. If you needed to learn something you learned it at work, on work time. If something new was introduced, IBM came in and conducted training, at work. For something big you might get sent to an IBM training center for a week. There was no need for (and no real way to do) any learning on your own outside of work.

They aren't really into tech outside of work.

There's a somewhat active community of COBOL developers here:

https://www.reddit.com/r/cobol/

If you're every really bored, search around the HN archives to find out how I accidentally founded that community as a result of a joke. :-)