There are at least three folder types in email:
I cannot add my Calendar entries to the folder structure in Runbox because they’re converted to post format (they resemble individual emails rather than events on a grid). As a result, I have to place the folders in a stub account not associated with my Runbox account.
However, I can still edit Calendar events if I use CalDav Sync on Desktop or DavDroid on Mobile (which I can confirm works without Play Services).
Can we create a server side option that allows us to dictate what kind of contents a folder is supposed to have?
Example Dialog: overflow Menu next to specific folder > Folder Contains:
[ ] Post Items
[ ] Calendar Events
[ ] People Entries