Slack CEO Stewart Butterfield and Away co-founder Jennifer Rubio. (Instagram Photo via @Jennifer)

Three weeks into his $27.7 billion honeymoon phase with Salesforce, Slack CEO Stewart Butterfield’s real wedding could have an unwelcome guest of sorts, in the form of rival Microsoft Teams.

The ironic, collaboration-software-technology twist was delivered in a tweet on Monday by Butterfield’s fiancée, Jen Rubio, co-founder and president of the luggage brand Away.

Rubio said that she and Butterfield — described by some as Silicon Valley’s newest “it” power couple — were planning to get married virtually in California next week. But the Office of the County Clerk in San Francisco says in its guidelines for video marriage services that couples need to have access to MS Teams.

It’s comical — and perhaps completely 2020 — to imagine Butterfield dressed at home on his wedding day, hunched over a mobile device trying to download Teams so that he can securely connect for his virtual ceremony. Some joked in replies to Rubio’s tweet that Teams would freeze halfway through the vows.

PREVIOUSLY: Bride and Zoom: Seattle couple marries in backyard with officiant and wedding guests on video call

Butterfield launched Slack, the popular workplace collaboration tool in 2013. When Microsoft announced the debut of Teams in 2016, Slack greeted the news with a full-page ad in The New York Times, telling the Redmond, Wash.-based tech giant that it was excited to have some competition in the space, but that succeeding with the tech was “harder than it looks.”

Earlier this year, Butterfield said Microsoft was not a competitor to Slack and told The Verge in May that “Microsoft is perhaps unhealthily preoccupied with killing us, and Teams is the vehicle to do that.”

Butterfield, 47, and Rubio, 33, got engaged at the end of May and had originally planned to have their wedding in Peru, but the COVID-19 pandemic scuttled those plans, Rubio said in an Instagram post. She announced a week ago in another Instagram post that the couple is expecting a child together and she detailed the struggle it took to get pregnant.

Butterfield was previously married to Caterina Fake. The two founded the photo-sharing site Flickr together in 2004 and split in 2007.

Salesforce’s acquisition of Slack is expected to close in the quarter ending in July 2021. It would be the largest acquisition in Salesforce’s history. The company previously scooped up Seattle-based Tableau Software for $15.7 billion.

Rubio’s Away is valued at $1.4 billion.

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