Upward’s nine-year-stay with the Berkshire outfit came to an end this Summer, with Boro boss Spencer Day moving fast to capture the signature of the accomplished midfielder.
Ryan originally started out with Beaconsfield SYCOB in July 2013, before signing for Burnham the following season.
Having moved to York Road for the 2014/15 season and been an ever-present figure, the 31-year-old left Maidenhead United as their longest serving player.
Boasting a wealth of experience in Non-League’s top flight, Upward has made over 150 appearances for The Magpies, also helping to deliver a National League South title in 2016/17.
Manager Spencer Day commented: “Ryan arrives from Maidenhead where he’s been a regular starter in The National League for the past six season after gaining promotion.
“His energy in centre midfield will be influential and he’s equally at home as defensive midfielder or number eight.
“The quality of player we need in order to take the next step and again with an infectious character that the Boro fans will love!”
Speaking at the Easy As HGV Stadium, Upward said: “I’ve been at Maidenhead for a long time and as soon as it went public that I left the club, Spencer showed a massive interest.
“He really wanted me to come to the club. The offer was good. It’s local enough for me and it’s a great Stadium with good fans.
“It’s a new challange, new chapter and I’m looking forward to the experience. I want to help the club to the Play-Offs. The club’s got a lot of potential and targets to reach.”