Not sure if any other telco has started yet, but Jazz is using IPv6 now.
I'm in an area where there isn't any PTCL coverage, so we had to set up an external LTE antenna and a Huawei B535 router with a Jazz Data SIM.
Just tested with my phone too. Jazz APN uses IPv4 only by default, but if you enable IPv6, save the APN and toggle flight mode on/off, you'll get IPv6 on your phone as well.