Question Moving to Plesk, LetsEncrypt Certificates

[iansen]

Hello,
I'm moving a website to a new Plesk powered server.
I would like to make the move seamless.
I plan on moving the backend first and keep the database on the old server until all the traffic switches to the new IP.
But I have an issue/question with/about the LetsEncrypt Certificates.
How can I keep both servers running with valid certificates, for a day or two until the DNS changes propagate?
Does requesting a new certificate for my domain in Plesk invalidate the old certificates?
How can I just use the old certificates until I make the change? I
I've tried uploading the pem in the domain configuration panel ...but it's saying it's invalid (although it's working fine on the old server).
Am I missing something?

I'm new to Plesk, sorry if my questions sound stupid .

Thanks in advance.

 

[Monty]

AFAIK, the old certificate will remain valid until its expiration date. So what you could do:

1. Lower the TTL of your domain to a low value (like 300 seconds) and wait until the previous TTL (usually 86400) has expired
2. Set up the website on the new server (without the valid certificate) and make sure everything is working
3. Change your DNS and point it to the new server and make sure that your authoritative nameservers are up to date
4. Install the Let's Encrypt certificate on the new server
5. If all goes well then you'll have a valid certificate on the new server and then you can take your time migrating the rest