This guide will cover an alternate way to launch Design Manager from iOS devices. This should be a temporary workaround until the next Workspace app is released to the Apple App Store.
First, make sure Citrix Workspace is installed to the device. You can browse to the Apple App store and search for Citrix Workspace App. Download and install.
Next, open Safari and browse to: https://login.designmanager.com
Enter your DM username and password and tap Log On
Click Download on the Launch.ica file
Click the arrow button to open the Downloads folder
Tap to open the .ICA file at the top of the list.
You should receive a popup that the application is Launching
Then open to your copy of Design Manager