I have a Crystal Sky 5.5 to use with my Mavic and Osmo.
It has worked with both however I switch on my CS and Osmo and the DJI apps on the CS are both the same  (version 4.0) and do not list OSMO in the device list and when connected to the Osmo via WiFi, a screen overlay appears:

Current DJI device: OSMO
Use the DJI GO app for this DJI device.

I used to have DJI GO and DJI GO 4.0 on two separate "icons" on the main screen of the CS.
Now the icons, when clicked, open the same programme, DJI Go 4.0 and I cannot use the CS with the OSMO.

Solution ?

On the home screen, tap the Settings icon.
Scroll down to Launcher Settings and tap it.
There you should have two selectable menus.
If you tap one of them you should get the option to select from the folowing:
-DJI GO 4.0
-DJI GO
-DJI Pilot
Tapping the DJI GO icon shoulk allow you to launch the older app for the Osmo.Then you just back out of the menus untill you are back on the home screen.

If you for some reason do not have this option i would suggest performing a factory reset of the CS.

StianGel Posted at 2017-11-24 17:22
On the home screen, tap the Settings icon.
Scroll down to Launcher Settings and tap it.
There you should have two selectable menus.

Well thanks so much for that StiianGel.
Don't know why it flipped over so both icons launched V4.00 but thanks to you I have now learned a bit more about the CS unit.

Cheers!!

What StianGel suggested is correct. Did you get the problem sorted out?