If decreasing the encryption strength resolves the issue, upgrading to 7.4 should resolve those issue. I have tested this scenario in the lab and found it is resolved in the 7.4 release train.
We have thousands of iOS users who use Pulse. We need to let them know if they can upgrade to iOS7 when it's released next week. I'm surprised Juniper doesn't release a statement about compatibilty with major software upgrades like this.
Pulse on iOS 7 seems to skew the initial login pages - specifically, we have noticed that the pre-logon notice, and the page to enter the login credentials seem to be stretched out and not resized correctly, based on screen resolution.
I did a generic test with Pulse 4.2R8 with iOS7 today. I was able to create a vpn tunnel and connect to resources through the tunnel. I will continue testing, but feel free to provide any additional feedback in this thread.
Juniper has identified an issue with Junos Pulse and iPhone 5s. Layer 3 VPN functionality on iOS 4.2r8 client will not work on iPhone 5s as iPhone 5s requires a 64 bit VPN plug-in. This issue does not affect iPhone 5c or any other devices running iOS7. Further updates can be found at: http://kb.pulsesecure.net/InfoCenter/index?page=content&id=KB28140&smlogin=true
