Ting Mobile is a popular MVNO carrier for years. Just like Google Fi, it is aimed at people who do not use a lot of cellular data, with the ability to mix and match levels for minutes, texts and data usage. One of Ting's major strengths lies in its ability to use a GSM or CDMA network, but this will soon disappear.
Ting currently allows customers to use GSM or CDMA SIM cards even on different lines of the same account. GSM cards use the T-Mobile network, while CDMA cards use Sprint. However, Ting today announced the end of its partnership with T-Mobile, and all existing GSM SIM cards will cease operation by December 19, 2020. In a press release, the company mentioned the uncertainty regarding the planned merger between T-Mobile and Sprint main reason to switch to Verizon.
Device compatibility will not be immediately clear once the transition is complete, but this decision will permanently prevent many phones from working with Ting. Verizon has a whitelist network that only certified phones can connect to, but even if this does not apply to MVNOs, many GSM-only devices (like imported Xiaomi phones) do not support most Verizon LTE tapes. Some Ting customers also use T-Mobile locked phones, which will certainly not work after the transition.
Ting has already removed all GSM-only phones from its online store and the company says Verizon support should be operational by the end of 2019.