As of yesterday, Ubuntu Software Center wants to upgrade the BIOS to version 0.1.35 while Lenovo is still only offering version 0.1.34.
Compare and contrast
Ubuntu Software Center
How could that happen?
Lenovo (updated; Oct 22 2018)
It indeed seems to have been the case that Canonical was ahead of Lenovo. But why and how is still a mystery: Since originally posting, Lenovo seems to have caught up with Canonical: both now refer to version 0.1.35.