on Sophos Firewall, if I update and regenerate the default CA, what are the implications?

On Sophos Firewall, if I update and regenerate the default CA, what are the implications?

I have a firewall that is setup, the default CA hasn't been customised so far.

I need to setup a S2S IPsec VPN with certificates and wanted to customise this before I did.

https://docs.sophos.com/nsg/sophos-firewall/18.5/Help/en-us/webhelp/onlinehelp/AdministratorHelp/Certificates/CertificateAuthorities/CertificatesDefaultCAUpdate/index.html

I can see that updating will result in regen of the CA, but will this have other implications, do I need an outage window?

I'm not using HTTPS decrypt, my SSL remote access VPN using a different CA set in the global settings.

Thanks in advance.