Converting Posts from Former Markdown Plugin

Before installing this plugin, I was using Markdown Extra. I would love to use MOSI but once I deactivate the former plugin, each post written in Markdown pre-your plugin now has the “Disable Markdown formatting” box checked and is displayed on the site with no conversion. I am left with the prospect of going through each and every post and unchecking the box, and my blog have almost 2000 entrys. Is there an easier way to do it?

Thanks in advance for your attention.

https://www.ads-software.com/plugins/markdown-on-save-improved/