OpenVPN renew CA and Server cert without renewing client certs?

[CoyoteKG]

Version: 2.5.2-RELEASE

My CA and OpenVPN certs expired few days ago.
I renewed those, restarted OpenVPN servers,
I did not renew client certs since those are valid until 2031.

But I was not able to connect to the server. I had this error

TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)

After I renewed user cert as well I was able to connect to OpenVPN.

Questions are:

1. Do I rly need to renew cert for all clients even they are not expired?
2. Is there any way to renew all certs in place, without any changes on client side?

This is example of exported client conf

dev tun
persist-tun
persist-key
ncp-disable
cipher AES-256-CBC
auth SHA256
tls-client
client
resolv-retry infinite
remote vpn.xxx.io 1195 udp4
lport 0
verify-x509-name "xxx VPN server" name
auth-user-pass
remote-cert-tls server
explicit-exit-notify

<ca>
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----
</ca>
<cert>
-----BEGIN CERTIFICATE-----
xxx
-----END CERTIFICATE-----
</cert>
<key>
-----BEGIN PRIVATE KEY-----
xxx
-----END PRIVATE KEY-----
</key>
key-direction 1
<tls-auth>
#
# 2048 bit OpenVPN static key
#
-----BEGIN OpenVPN Static key V1-----
xxx
-----END OpenVPN Static key V1-----
</tls-auth>

[Jarhead]

@coyotekg The client certs use the CA as the issuer just like the server certs do so yes, you would need to change them.