Cal Henderson, Slack’s chief technology officer and sole remaining cofounder, is stepping down from the role effective immediately, but will remain at the company until March 1, according to a memo viewed by Fortune. He will be replaced by Salesforce cofounder and CTO Parker Harris, who will shift his focus to the Slack business. It was not immediately clear who will replace Harris as the Salesforce CTO.

The change, which is being announced internally to employees on Friday morning, comes just three months after Slack CEO Lidiane Jones stepped down less than one year into the job, and 13 months after Slack’s founding CEO, Stewart Butterfield, announced that he was leaving the company.

“I think there’s an average amount of time that founders stay after an acquisition, and this is way longer than that,” a Salesforce spokesperson told Fortune in regards to Henderson’s departure. “This was not a surprise. This was something that’s been talked about for quite some time.”

Salesforce acquired Slack in 2021 for $27.7 billion. But the integration of the popular workplace chat app into Salesforce, one of the leading providers of cloud-based business software, has been marked by culture clashes and turnover.

“The problem has been, there’s no incorporation of the Slack culture into the Salesforce culture,” Butterfield said in a Slack all-hands last January, according to an audio recording of the meeting obtained by Fortune. “And unless there is some element of that, then it’s not integration in any sense. It’s just the elimination.”

Last year, Salesforce abandoned Slack’s recently remodeled San Francisco headquarters and moved employees into its 61-story Salesforce Tower.

With Henderson’s exit, Slack is officially devoid of all its cofounders, its senior leadership now composed of Salesforce executives aside from its chief product officer, Noah Weiss, who’s been with Slack for eight years. Denise Dresser, a 12-year Salesforce veteran, took the reins as Slack CEO in November when Jones announced she was leaving to become CEO at dating app Bumble. Following this third CEO installment at Slack, Fortune exclusively reported three executives, including Neil Shah, who served as the workplace messaging service’s COO for the past eight years, left the company. The new Slack COO is also a Salesforce executive, Sarah Walker.

“It’s changing as a lot of the more tenured folks leave, but there’s still a lot of long-term people that are rolling their eyes,” a Slack employee who requested anonymity because they weren’t authorized to speak publicly told Fortune earlier this month. “Especially considering execs have like a year shelf life here. A lot of jokes about what they’re actually going to accomplish here. Lots of concerns around the pivot from product culture to sales culture, too.”

Salesforce, which generated $25.6 billion in revenue in the nine months ended Oct. 31, does not break out Slack revenue. In 2021, the last full year for which Slack reported financials as a stand-alone company, it generated $900 million in annual revenue.

While Salesforce’s overall revenue growth rate has slowed in recent years, the company has boosted its operating profit margins, thanks in part to a focus on cost cutting, including reducing its office space and a round of layoffs in early 2023.

“We’re one company, you know, we’ve been one company for quite a few years now,” the Salesforce spokesperson said. “When you think about the integration that’s happened, particularly in the sales side, like, it’s actually embedded. So that’s just kind of, I guess, the nature of how we kind of evolved, as one company.”

Friday’s leadership shake-up also comes after an apparent miscommunication in the C-suite, with Fortune reporting on a memo from Slack CTO Henderson’s chief of staff that a strict hiring freeze has been implemented. A Salesforce spokesperson claimed this was a misstatement and that the company would continue to hire “strategically.”

“We are not freezing hiring in any departments,” the Salesforce spokesperson said.

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