James,

All our developer program content including sigma tile requires developer kit. Freemium has limited capability and you will not have access to Composer which is required for these training contents. I would encourage you to download and install  the developer kit.

Thingworx MFG 8.1 was released last week. We haven't got an opportunity to test using that release. Having said that I do not see any problem with respect to Sigma Tile and it should work.

Thanks,

Varathan