I've been having issues with ipv6 since upgrading the firware to 180305(i have canadian version) seems to drop out randomly not just for a while but for days and comes back randomly Ipv6 can't obtain address,  and I wanted to downgrade to stock version that came with the device on purchase but I can't find it on the tp link website for canada, only 180305 is listed. Where can I get the older version from? Would trying out ddwrt to be a good idea?

I've very much surface knowledge of networking, not a advanced user.

Thanks