Apple released a change two weeks ago to the way that the codesign tool works in regards to applications that have been signed on a Mac in OSX El Capitan. The sha1 has can no longer be accepted for signature validation purposes. It must be formatted as sha256 for the signature to be created to successfully validate. Since Mobility Suite's codesign tool on the backend uses Linux, we have upgraded the signature to use sha256 instead of sha1. SaaS customers have had this patch applied on the 'appcenterhq.com' domain. The patch will be included in the upcoming Mobility Suite 5.5 .iso release for On-Prem customers.
The OSX Release that brought these changes is as follows:
OS X El Capitan v10.11.4
INFO:
https://developer.apple.com/osx/download/
DOWNLOAD:
https://itunes.apple.com/us/app/os-x-el-capitan/id1018109117?mt=12
Error message seen in device logs:
"Domain=MIInstallerErrorDomain Code=13 "Failed to verify code signature" (The application does not have a valid signature.)"