Takedown lever retaining wire?

[tranger1955]

I recently purchased a 2.0 40SW. Following along with a youtube video, I was installing an apex trigger. The video mentioned a "takedown lever retaining wire". There's no groove in the locking block for the wire. Does the M&P 2.0 need the wire?

 

[jurek]

M&P9 2.0 doesn't have it anymore. I think this also applies to 40S&W

 

[tranger1955]

Many thanks!