I'm using NFS and I have the following problem.
After ~100 days, the client and server lose connection, but the client doesn't know about this, it gives no error. The problem is that the changes on the server side aren't visible on the client side.

The nfs options are: "noatime, nolock, hard, udp, notcp, nosuid, nodev, rsize=8192, wsize=8192, actimeo=60"

The kernel version is: built with 250 Hz.

Is this an already corrected issue in a kernel version? Or are my options wrong?