Unable to install Unpublished App on merchant stores

[dsahani]

Hello There,

We have a Shopify Unpublished App which we used to sync the product, variants, inventory, order fulfillment, etc from our B2B platform to Shopify. We are using it since 2017 and it was working really well and also working great for existing stores but now we are unable to install it on further stores. 

We are getting following error,
This app is currently unsupported. The developer needs to update it before you can install it. You can contact the developer via their Shopify App Store page or website.

Here is the screenshot for reference:

We have updated all our API to latest version there is not any API depreciation warning.

Any help will be appreciated! 

Thanks in advance!

[RSHA]

I'm also facing the same issue.