New warning for millions of Galaxy usersAFP via Getty ImagesThis is becoming an awkward week for Samsung, as it releases Februarys monthly security update with Androids most critical fix missing at least for now. Google has confirmed devices are under attack, and has provided a fix in its Android release. But not for Samsung. We have also seen the new Galaxy S25 given a firmware update that only includes security updates up to December 2024, and the continued delay to the release of One UI 7 / Android 15 to its recent flagships.If ever there was a time to ensure youre on Samsungs monthly update schedule, its now. While there are always delays in getting updates out across Samsungs user base, you want to get those updates as soon as you can. Once you fall off the monthly schedule, you need to consider an upgrade. So it is for owners of Galaxy S21 series phones, which have just been given the bad news: Say goodbye to monthly updates on your Galaxy S21, S21+, or S21 Ultra, as SamMobile neatly puts it.Security updates have not stopped completely, but have been downgraded to a quarterly schedule. Going forward, for at least a year, Samsung will release a security update for the original Galaxy S21 trio once every three months. The Galaxy S21 FE, however, will continue to receive monthly updates, as the FE model hit retail shelves almost a year after its non-FE counterparts.Were now keeping our phones longer between upgrades, which is why the guaranteed minimum support periods are extending across the board. It is clear that this update decision from Samsung will affect millions of users, and while three-monthly updates is better than no updates, it doesnt help when theres an urgent fix mid-cycle.MORE FOR YOUThis is just the tip of an alarming iceberg when it comes to Android updates, though. Somewhere between 25% and 33% of the worldwide user base use devices that have completely fallen off support, which is one of the reasons Android is a riskier proposition than iPhone. And in our new world of BYOD, that risk extends from the home into enterprises and all the company systems those phones log into.Thats why Google has upped the ante with its Play Integrity API to enable app developers to check the security updates and OS status of phones before determining how much functionality that user on that device will be allowed.Meantime, if youre an S21 owner, my strong advice would be to move to a phone on a monthly schedule. As Phone Arena warns, while this doesnt mean that Galaxy S21 owners will no longer get security patches, its a warning that these phones are four years old and that you should probably think about upgrading to a new flagship. It doesnt have to be brand new the secondary market is fine, if the device you buy has some time left to run. You can see Samsungs update schedule here.