The Center City skyline is a little bit darker as of Monday night, when Peco turned off its iconic Crown Lights for the first time in a decade.

But don’t fret, Philadelphians: The lights will be back on sometime this fall, the energy company said, after they undergo system upgrades.

The light display has been delivering messages from atop Peco’s 23rd and Market Street headquarters since July 4, 1976. It has lit up more than 17,500 messages since then, Peco said.

The two-million-plus energy-efficient color LED lights have celebrated wins, including the Eagles’ Super Bowl victory, and marked important city events, such as the 2016 Democratic National Convention and Pope Francis’ 2015 visit.

Recently, they lit up to honor health-care workers on the front lines of the coronavirus pandemic.

The display last went dark for maintenance in 2009.

The top of the building gave one last message Monday night: “See You Again in the Fall!”

Over the years, Peco allowed people to submit messages for the community via an online form. It will no longer take those submissions while the lights sit dark, but it said fans can check out virtual “Crown Lights” displays on Facebook.