Sorry the app does not provide a view of "all starred messages no matter how old".
There is a way to sort a folder by "starred and unread" (Menu -> Sort in any folder's message list) and it can be saved as default (in the same menu).
This will only include starred messages from whatever number of messages that the app "synced to" the phone, not "all starred no matter how old".
You can increase this (number of messages that the app sync to the phone) by doing this:
- Long pressing on the account, on the app's main screen -> Options and folders -> account options
- Setting "messages to sync" and "messages to cache" to values like these:
sync = 100 (default is 50), cache = 250 (default)
sync = 250, cache = 500
sync = 500, cache = 1000
sync = by date range (e.g. 14 days, 30 days..), cache = 250 (default)
The more messages the app it set to sync to the device, the more work it takes (in terms of battery / traffic), so jumping to into the "thousands" values is not recommended.