Support answered my questions. First the support statement is what is is for 1910, that it hasn't been certified yet, although there were no specific issues which could be described to me. Second, there appears to be mis-information in the documentation.
Page: 47 (Upgrade Checklist)
Run all Windows updates
- "When you are finished, generate a new 2048-bit publishing certificate on your primary application server."
Per support, this might be there as a good practice, to ensure you don't forget to keep the cert updated (mine was created for 5 years), but that doing this step will invalidate what you've done with the old cert. This should only be done under a specific effort when the cert needs to be updated.