What happened to the Visio SDK?

Not applicable

I've just moved from Visio 2016 Professional to Visio Online Plan 2, but some things seem to be going wrong especially when picking up stencils I created in the previous version. I've noticed that when I try to edit one of these stencils it can suddenly vanish - and if I then update all the shapes created from that stencil they vanish too. Have others found this?

I've also noticed that the SDK I was using from 2013 and 2016 now appears to be incompatible with the Online version. I have no access to it anymore and so I cannot use it as a source for the code library.

Is this true? Have others found this? Or is it my mistake?

I would really like to understand what's going on.

Simon Fawcett