Ting, a mobile virtual network operator (MVNO) that currently resells wireless service from Sprint, is adding a partner whose phones use the GSM technology, starting in February 2015.
Although the Ting is reluctant to name the GSM provider, one look at the URL in this coverage map confirms that T-Mobile is behind the scenes.
Once the switch is flipped, Ting will support more than 80 percent of the smartphones released over the last few years. What's more, customers will be able to have GSM and CDMA handsets on the same account -- in other words, both T-Mobile and Sprint phones -- a first for the mobile industry.
There are more details in Ting's blog post. If you want to check whether Ting will support your current smartphone come February, head to the compatibility checker.