A new addition to The Dole Mansion last year, the 4th Fridays Art Event, hasn’t stopped evolving. Having built up a following—drawing about 1,000 art enthusiasts a month—the event will celebrate its 70th birthday on Jan. 24 with several new additions. Among them are a food truck, an Artist Connect program and an after-hours Late Night at The Dole event with live music, dancing and a cash bar in the mansion’s Listening Room. It’s more than an art show, said Nancy Merkling, the event’s creator and producer, who first began 4th Fridays in 2011 at the Starline Factory in Harvard.