Questions:
Do I need a new registration with the V2 API or can I just change the uri in my account file and start renew of my certs?
If I need a new registration, is there any relationship between the certs, issued with V1 and those issued with V2? I.e. is it necessary to revoke the V1 certs before starting to create them with V2?
During testing of my V2 client with challenge dns-01, I often get DNS errors like “Incorrect TXT record” or “NXDOMAIN” while I see the TXT record i.e. at 8.8.8.8. What might me myy problem? I have the ttl set to 60.
V1 and V2 simply refer to the way in which you obtain a cert.
The certs themselves have no reference to, nor understanding of, V1/V2.
[note: V2 is now required]
Most likely, the zone has not completely replicated to all authoritative DNS servers.
You should pause for enough time to complete that synchronization.