A number of customers with TomTom sat-navs have been told that their devices will no longer receive map updates.
“Your maps will become out-of-date and as such navigation will be less accurate,” the firm told customers.
“It has become clear that some of our older generation navigation devices do not have sufficient resources to run the newest maps and software.”
Some devices that were on sale in 2017 will stop being updated and the BBC has asked TomTom for comment.
The firm has published a list of affected models online.
In an email to customers, the firm added: “We will continue to provide quick GPS fix updates so your device will continue to function as it does now.”
The BBC has spoken to two affected customers, one of whom was given her sat-nav at Christmas.
Paula Hatcher’s partner bought her the Start 20 device because her previous sat-nav – the same model – had not come with lifetime maps.
“I haven’t even had the opportunity to update it even once, since the email I received this morning [advised] the withdrawal of lifetime maps,” she said.
Photographer Rab Harling told the BBC he purchased a TomTom Start 42 from Argos in July last year.
The device first went on sale in May 2016 and is still available at a number of online retail sites that say it offers “four free map updates a year for the lifetime of your device”.
Mr Harling told the BBC he was unhappy with TomTom’s decision to stop providing this service.
“You expect a product to be of satisfactory use for a reasonable period of time,” he said, adding that he wasn’t pleased with the device’s current performance either.
“I think seven months for a sat-nav’s not really very long especially when it wasn’t very good in the first place.”
TomTom’s sales of devices direct to customers have recently been in “severe decline”, according to analyst Chris Jones at Canalys.
“Clearly they’ve identified a business market for future growth – that includes navigation and traffic services integrated into cars,” he explained.
He said the market for personal sat-navs had been eroded by the rise of smartphone apps that offer similar services and frequent updates.
“Within months the [sat-navs] will quickly become out-of-date when those updates stop appearing,” he added.
“It’s not just new roads, it’s [information about] features on roads – road signs, speed limits, rights of way and crossings.”