MetroPCS's legacy has come to an end as T-Mobile shut down the last of its CDMA network in New York, Dallas and Miami, which -- combined -- had 190,000 customers still hanging on.

A year ago T-Mobile US Inc. shut down MetroPCS's 3G CDMA in Las Vegas; Hartford, Conn. and Boston, and it has been warning of the June 21, 2015 deadline for the remainder of the network for awhile now, incentivizing those lingering customers to upgrade to its GSM or LTE networks with promotional data pricing and free phone upgrades. (See T-Mobile's MetroPCS Offers $50 Unlimited LTE.)

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Even so, the carrier still had around 190,000 customers using the CDMA network as of Friday, down from 300,000 in mid-May. A T-Mobile spokesman said the carrier would have updated numbers by the end of the week -- as it expected many to upgrade as soon as they lost service -- but that it won't be sharing how many of those customers upgraded to 3G or 4G with T-Mobile. As a point of reference, 92% upgraded last year after CDMA was shut down in Las Vegas, Hartford and Boston. (See T-Mobile & MetroPCS Complete Merger.)

The process of shutting down MetroPCS markets has cost the carrier between $375 million to $475 million, but it's a crucial part of its strategy to refarm the AWS and PCS spectrum for LTE. At the end of the first quarter, it had repurposed about 80% of MetroPCS spectrum and integrated it into its LTE network, and Sunday's shutdown will allow it to complete the remaining 20%, creating 20x20MHz LTE channels in those markets. (See T-Mobile Reports Q1 Revenue of $7.8B, T-Mobile Customers Use the Most LTE Data and T-Mobile Quietly Kicks Off Double-Wide 4G.)

— Sarah Thomas, , Editorial Operations Director, Light Reading