Appears that way:
https://www.symantec.com/connect/blogs/symantec-mobility-suite-sms-eol-announcement
Doesn't appear they will be replacing it with anything going forward:
Symantec has concluded that Mobility Suite does not have a place in the new unified security strategy. Mobility Suite’s share of the EMM market had been declining and it would require significant investment to become on par with and eventually surpass the current market leaders. Given that the key tenant of the unified security strategy is to provide customers with cloud-based solutions moving forward, the decision was made to discontinue investing in SMS and focus on next generation unified security solutions.