If only the 10/100 license is installed in Vivado 2015.1, the TEMAC IP might stop working.
10/100 licensing has been removed from TEMAC.
The TEMAC core is now controlled by the TEMAC licensing for either 10/100 or 1G or 2.5G.
All 10/100 customers were automatically upgraded and have access to the TEMAC license key.
However, if you only have the 10/100 license installed in 2015.1, the IP might stop working.
If this is the case, you will need to generate the new TEMAC license key.