We recently went live with a SharePoint 2013 project, the projects launch included the SharePoint NewsFeed iOS App too.
However, before go live we noticed an issue where under some circumstances the SharePoint Newsfeed iOS App (1.0-1.2) would crash when trying to sign in.
After a period of troubleshooting, we found that the app only crashed when connecting directly to some of our SharePoint 2013 sites. But those same sites would work fine when connecting externally via our TMG.
We enabled Kerberos on the same troublesome sites to allow for Single Sign On (SSO) for both our Mac & PC clients, it appears that by enabling SSO we inadvertently caused the Newsfeed App to crash (but as the primary site compromised various SharePoint sites, SSO was needed for both Mac & PC – leading to being stuck between a rock & a hard place).
Others have had the issue too, & advised various threads advised that SSO did cause the issue.
When connecting externally via TMG, the app would work fine as it would not be presented with a Kerberos authentication request.
To resolve our SharePoint Team created a new URL for the Newsfeed app that was not kerberized, once this was done we pointed the app to that new URL & it worked fine both internally & externally.