Skype for Business Server requirements for Cloud PBX with on-premises PSTN connectivity

Gregory Williams, I'm are not aware of any isues. However at the same time, since this is a non-supported combination, I'm not aware of anyone who has tried it. The solution was not designed, build or tested with interoperability with Lync Server 2010 in mind. If you run into any issues in your environment that could be connected to this unsuppoted configuration, support would not even know if this combination is supposed to work -- and you might have to move to a fully supported architecture for troubleshooting your issue. Future hotfixes/changes/improvements will be build without considering Lync Server 2010. Ultimately, since this is an unsupported configuration, no other customers are (or should) run this configuration. As you can see, there is a lot of risk invovled.