Hi fmouse,
Umm.. you are correct.
There is no x32 update for Workstation past version 10.
For version 12.x you need to run a x64 host operating system.
So you would have to upgrade your ubuntu from 32 bits to 64 bits.
It depends on a bunch of factors if this is easy or difficult.
In the case you partitioned your disk in the host so that your data and home folders are in different folders then it is pretty much a matter of overwriting the host operating system parts and keeping your data and home partitions.
That tends to work reasonably well. Of course it all depends on how much you customized the OS and if your host actually has a 64 bit processor.
PS: As you might have noticed Workstation 14 has been released just yesterday, beware though that you need a recent 64 bit processor for that one or you'll just end up wasting a lot of time.
PS 2: Forgot to add the host OS support KB Supported host operating systems for VMware Workstation (2088579) | VMware KB
TL;DR the last Ubuntu host OS that Workstation 10 supports is version 14.10, ubuntu 16.04 is sadly not supported for WS10.
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Wil