Windows 10 will receive security updates for the last time in October. The switch to Windows 11 should not be postponed until the new year - but it is not yet urgent in terms of weeks and months. Windows 10 is currently just as secure as Windows 11.
Windows 11 can no longer be activated with licence keys for 7, 8 and 8.1. So if you upgrade from Windows 10 and the system refuses to activate Windows 11, you may be using Windows 10 with a licence key for 7, 8 or 8.1.
With Windows 10 licence keys, on the other hand, Windows 11 can be activated indefinitely, i.e. for many years to come. Some users are therefore currently concerned that it will be impossible to activate Windows 11 with Windows 10 licences in the foreseeable future.
Most recently, Microsoft ended the ability to activate Windows 11 with licence keys for Windows 7, 8 and 8.1 only after the date for the end of the delivery of security updates for Windows 10 had been known for more than a year. If Microsoft maintains this practice, no one using Windows 10 with a genuine Windows 10 licence will have to worry about purchasing a licence for Windows 11 before the end of life of Windows 11 is announced and a successor is announced.