Can't Activate on 2.3.13

I know, I know – we’re running an outdated version of WC. However, we have a large store with a lot of customizations and so it takes us a bit longer to update. And we didn’t know that your plugin upgraded Matt’s plugin! Now that we know that, we’re in the process of migrating EVERYTHING. That said, I wanted to see how things were just by first upgrading to WC Vendors 1.8.7 from PV 1.5.0.2. Problem is, I can’t even activate the free plugin. Your help says that 2.3+ is supported. I’ve tried other activation solutions you’ve reported but none are working. Or, are you simply not supporting 2.3 any longer? A fresh copy of WC 2.3.13 doesn’t work either.

https://ww.wp.xz.cn/plugins/wc-vendors/