To legions of executives, journalists and politicians — even the leader of the free world — they were once-indispensable devices for staying connected when ordinary cellphones wouldn’t suffice. Anything else was for amateurs.

The devices, with the quirky-sounding name BlackBerry and the QWERTY keyboard that conditioned many people to type with their thumbs, were more ubiquitous than iPhones during the late 2000s.

But as of Tuesday, Blackberry models that use the company’s operating systems will go the way of the Commodore computer and the LaserDisc. So will their trademark trackballs and Tic Tac-sized letter keys.

As part of an “end of life” decommissioning program that was initially announced in 2020, BlackBerry said that as of Jan. 4, 2022, it would no longer support the devices as the Canadian company completes its yearslong shift from making mobile phones to a software-based business model.

For some, the deadline represents a wistful conclusion to an era before touch screens, Apple Pay and TikTok, when BlackBerries dominated offices, airport lounges and the West Wing.

President Barack Obama famously clung to his BlackBerry after taking office, prompting the White House to strip it down for security reasons.

Kevin Michaluk, the founder of CrackBerry, a website and forum dedicated to the once-popular devices, waxed nostalgic on Monday about the rise and fall of the technology. In 2016, BlackBerry abandoned making phones, devices that the company, previously named Research in Motion, had come to define.

“The initial sadness for me has been lived several times,” said Mr. Michaluk, who uses the nickname CrackBerry Kevin. “To use my real name, people don’t know who the hell I am.”

Mr. Michaluk, 41, who lives in Winnipeg, Manitoba, said that BlackBerry devices, featuring model names like the Curve, Bold, Storm and Pearl, enhanced productivity without all of the distractions that come with iPhones.

“It feels like they’re causing A.D.D. for most of us, rather than productivity right now,” he said of iPhones. “We went from analog phones to the pendulum swinging too far. You can’t actually get anything done on it because you’re constantly bombarded by sensory overload.”

In a message posted on its website on Dec. 22, BlackBerry reminded users that devices running legacy services over cellular networks or WiFi would no longer be able to receive or send text messages or other data, make phone calls or contact 911.

The company, which thanked its users for their loyalty over the years, did not immediately comment further on Monday.

On its website, the company pointed out that Android-powered models like the BlackBerry KEY2, which was manufactured by the Chinese company TCL under a partnership that ended in 2020, would not be affected by the change.

That might come as a relief to Carrie Bradshaw, Sarah Jessica Parker’s character in “And Just Like That,” the reboot of “Sex and the City,” who uses a BlackBerry KEY2.

Few people came to be more synonymous with BlackBerry than did Mr. Obama, whose reliance — ahem, addiction — to his mobile device presented a conundrum when he was elected to the presidency in 2008.

Writing in his 2020 memoir, “A Promised Land,” Mr. Obama recalled, “My team did throw me one bone when it came to freedom: I was able to keep my BlackBerry — or, rather, I was given a new, specially modified device, approved only after several weeks of negotiations with various cybersecurity personnel.”

Mr. Obama said that he could send or receive emails only from a list of 20 or so vetted contacts on his BlackBerry, which had its headphone jack and microphone removed and did not work as a phone.

“Michelle joked that my BlackBerry was like one of those play phones you give toddlers,” he said, “where they get to press buttons and it makes noises and things light up but nothing actually happens.”

Adam Matlock, 37, who runs TechOdyssey, a technology review channel on YouTube, said on Monday that he received many messages from BlackBerry users expressing concerns about no longer being able to use the devices.

“They’ve been holding onto it for so long because there’s no replacement,” he said. “I always felt like BlackBerries, they were special because they had a keyboard and were not trying to be another phone with a touch screen.”

Even if BlackBerry didn’t decommission its older devices, Mr. Matlock said, they would be virtually impossible to run once major wireless carriers like Verizon, AT&T and T-Mobile phase out 3G technology during the next few years.

“I think it’s unfortunate that they’re ending support for it,” he said. “I understand the decision because the platform itself is pretty much obsolete at this point.”

Mr. Matlock, who lives in Houston, keeps some of his vintage devices in his office, he said, like the BlackBerry 7100g.

“They always felt kind of special to me,” he said.

Mr. Michaluk, or Crackberry Kevin, said his favorite model was the BlackBerry Bold 9000 because it had leather on the back.

“I have a little shelf with a little kickstand that it leans against,” he said. “Let’s call it a tasteful shrine.”

One of the first models that he owned was the BlackBerry 8700, which had a jog wheel on the side that let users scroll through menus and messages.

“It was a little tank,” he said. “You could throw the thing across the room like a baseball, and it would keep working.”

Mr. Michaluk now uses an iPhone.

“I’m now OK with that,” he said.

William Lamb contributed reporting.