Question about compatibility between major kernel upgrades

Hi,=0A=
=0A=
First, I'd like to thank you for the amazing work all of the supporters did=
 for this important project=0A=
=0A=
I have a question about checkpoint/restore compatibility across major kerne=
l upgrades.=0A=
=0A=
My company is evaluating CRIU as part of an OS upgrade flow.=0A=
The idea is to run a container with the target userspace on the old host OS=
 (so still on the old kernel), prepare our main process in the desired post=
-upgrade state, and dump it to disk with CRIU.=0A=
After upgrading the host OS and kernel, we would restore that process on th=
e upgraded system.=0A=
=0A=
Our main concern is long upgrade gaps. Some users may upgrade only once eve=
ry 5-10 years.=0A=
In that case, how much can we rely on a CRIU dump created on the old system=
 being restorable on the newer kernel?=0A=
Is restore across major kernel upgrades something that is expected to work,=
 or is there no compatibility guarantee for that?=0A=
=0A=
As a fallback, we are considering running a VM with the target OS on the ol=
d system, creating the CRIU dump there, and then restoring after the host u=
pgrade.=0A=
Would that reduce the compatibility risk compared to using a container with=
 the target userspace on the old host?=0A=
=0A=
For context, the host is Ubuntu LTS, and the container image or guest OS wo=
uld also be based on Ubuntu LTS.=0A=
=0A=
Thank you,=0A=
Tom=