Microsoft released update that removes the Windows 10 upgrade offer

Windows Update

This update removes the Get Windows 10 app and other software related to the Windows 10 free upgrade offer that expired on July 29, 2016. For a complete list of the software removed by this Windows Update, see the update replacement information.

This update is available on Windows Update. You may have to restart the computer after you apply this update.

Update replaces the following previously-released software:

KB 3035583 — Update installs Get Windows 10 app in Windows 8.1 and Windows 7 SP1
KB 3064683 — Windows 8.1 OOBE modifications to reserve Windows 10
KB 3072318 — Update for Windows 8.1 OOBE to upgrade to Windows 10
KB 3090045 — Windows Update for reserved devices in Windows 8.1 or Windows 7 SP1
KB 3123862 — Updated capabilities to upgrade Windows 8.1 and Windows 7
KB 3173040 — Windows 8.1 and Windows 7 SP1 end of free upgrade offer notification
KB 3146449 — Updated Internet Explorer 11 capabilities to upgrade Windows 8.1 and Windows 7

After KB3184143 is applied your Windows 7 and 8.1 system will be clear of any and all Windows 10 related free upgrade software.

Source: Microsoft