I am trialing a 4.9 Linux kernel on our mail server. The 4.8 kernel was supposed to have some improvements in NFS but broke something critical to IMAP and Pine so we reverted to the old 2.6 kernel. The 4.9 kernel is purported to have fixed some NFS issues in 4.8 and also has numerous improvements for the Skylake processor which happens to be the CPUs we are using in our servers. It purports to address issues with the graphics driver in Skylake and in the reset code (which has been a problem, to reboot the physical servers we have to physically power them down and back up with the current 4.8 kernels).
If you experience an operation failed in an attempt to fetch mail or any strangeness in pine please notify support right away, e-mail firstname.lastname@example.org or call 206-812-0051, if you don’t get me live leave a message.