Paul, this does not have a fixed magazine. It is also NOT CT compliant. All S&W M&P 15 rifles are banned in CT, no matter what features they have. It is on the list of banned weapons here >>> https://portal.ct.gov/-/media/DESPP/SLFU/firearms/assaultweaponspdf.pdf
Stay safe & have a great day!

Unfortunately, this would be a No, sorry. More info below on the ban and the rules to keep prior owned Banned weapons.
https://giffords.org/lawcenter/state-laws/assault-weapons-in-connecticut/#:~:text=Connecticut%20broadly%20prohibits%20any%20person%20from%20possessing%20an%20assault%20weapon.

Hi Paul and welcome. Yes Sir it is. Details under Rifles here: budsgunshop.com/feeds/state_reg/connecticut_restrictions.pdf - Cheers and stay safe!