Undoubtedly, this is an XPS 8930. Windows Update just started offering me BIOS 0.1.1.26 for my XPS 8930, even though I have already installed 1.1.26 (without the lead 0.) downloaded directly from Dell and using the F12 Flash Update option.  This  also means the OP has UEFI Capsule Updates enabled in BIOS setup which is required to allow BIOS updates to be installed via Windows Update.
Update 1.1.26 is now appearing on Windows Optional updates, no problem installing from there.
XPS 8930, BIOS Update 1.1.26