Is DynDNS supported on RouterOS 3.7 in any fashion?
No. You can use ChangeIP.com and point DynDNS.org hostnames to them using a CNAME if you wish. DynDNS will lock your account often enough that it’s not worth it ; ) (cheap shot)
How do I use ChangeIP.com with a RouterBoard (specifically a RB192)?
http://wiki.mikrotik.com/index.php?title=Dynamic_DNS_Update_Script_for_ChangeIP.com
Be sure you have the newest RouterOS on there … 3.4 and 3.5 had scripting problems, the rest should work okay. Let me know if you have any issues.