Cures Act - USCDI - C-CDAv21

Cures Act USCDI/ C-CDAv21 certification. I am looking for SDA3 examples for Newman-Bates-Kid/registry settings/advices on how to learn / whatever is helpful. InterSystems  xsl files are clean but I am not working very often with xsl. I am mainly looking at Provenance and Clinical Notes, the 2 last errors we have. InterSystems documentation, so far I know, is very poor: only classes and some pages. Support has a small knowledge about SDA3 -> C-CDAv21 even if they try very hard to help.

Of course I am wondering if my company is using an almost dead technology. Is everybody on fhir now? Are we the only one working on this certification?

Thanks for any advice

sylvie