Can I delete Custom Settings in Managed package salesforce?
Similar to the question above. We moved all our custom settings into one custom setting.
I was thinking once our subscribers upgrade to the new custom settings, we can ask them to manually delete the deprecated custom settings, and then in the next available package make sure they are deleted from our app/apex/code.
I realize this will require some coordination, but is it technically possible?
So following Salesforce documentation it is possible to delete if you are using the first generation package ->
you will need to request the client to delete by themselves, but if you've added it as protected it won't show up to the client to delete -> 
In any case, you will need to contact Salesforce to delete it from the managed package, you can find more info here : https://developer.salesforce.com/docs/atlas.en-us.sfdx_dev.meta/sfdx_dev/packaging_packageable_components.htm#mdc_custom_setting
