any one tell how to update rooted m9+ taiwan v1.85.401.6 to latest ota updates

Can any one tell me why we we need stock recovery .... and I had flash 1.85.401.5 after that again fail to update v 1.86.401.6 can any one help me and give a tutorial how to update rooted HTC One M9 plus Taiwan and my ota version is 1.85.401.6.
I have showing new updates available but when I updates it downloaded but fail to updates.....plz plz any one help me

Download from this link