all depends on your pki CA root certificate state. if it is still valid,
- renew openvn certificate
- paste key and public cert in openvpn panel
you will need then to do the same for clients only if the CA root cert has also reach its end of life and needed to be renewed. Plus you will need to do update also every other key/ certificates.
if your CA is almost at its end , you might rather want to do it as you are there. waiting might make it happen at a moment you have all your roadwarriors away