"A lot of people are going to be surprised by how a big a release it is, and I think it's going to force the entire HR industry to respond to it," said Sacks, a veteran of PayPal, and founder of the work-chat app Yammer.
In Z2, Zenefits is offering its own payroll service to customers for the first time.
Z2 also features a suite of fully integrated apps for a slew of functions, including expense reporting, stock options, performance management, recruiting and productivity. Zenefits has partnered with 17 companies to provide those apps — including Salesforce, Slack, Quickbooks, Expensify and eShares. It also has built Z2 to allow potentially hundreds of other third-party applications to be integrated into the system.
"Zenefits was the first all-in-one solution to the market three years ago," Sacks said. "What we're doing with this release is redefining what 'all-in-one' means, and the way to have that is through partners. There's no way that one company can do everything."
Z2 also will offer small businesses the ability to browse thousands of health insurance plans. To help narrow their choices, businesses will also be able to see how cost-effective those health plans are for individual workers, and how close geographically doctors in a plan's provider network are to employees.
Sacks is more than ready for the different-looking future that he believes Z2 will bring. For the past eight months, Sacks has been dealing with the fallout of a series of scandals at Zenefits, which had resulted in the then-chief operating officer taking over as CEO from Parker Conrad in February.
Under Conrad's watch, Zenefits had grown spectacularly with its HR software platform, eventually getting valued by investors as $4 billion.
But there were problems — a number of problems — at the San Francisco-based company.
First, it was revealed that many of the health insurance brokers Zenefits had on staff were not licensed to sell plans in states where Zenefits was operating.
Then, Sacks learned from Zenefits' lawyers that Conrad had written a piece of software — the so-called macro — that allowed company workers to satisfy California broker licensing requirements without actually doing the required work. That discovery led to Conrad's resignation, under pressure from Zenefits' board.
In the following months, there was a series of stories about the hard-driving, often hard-partying atmosphere at Zenefits, where big deals were celebrated with staffers gathering to down shots of alcohol.
A June 2015 email that Business Insider obtained revealed that Zenefits' director of real estate and workplace services admonished employees not to "smoke, drink, eat or have sex" in the building stairwells, where the building's manager reported that cups of beers, cigarettes and used condoms had been found.
During a recent interview with CNBC, Sacks still cringed about that email. He noted that Zenefits isn't the only the tenant in the building, so it's not clear that the company's workers were the guilty parties.