(Bloomberg) -- Uber Technologies Inc. is postponing its return-to-office date from September to Oct. 25, and has told employees that it could be further delayed depending on the global coronavirus case load.

In an email to staff on Thursday, Uber Chief Executive Officer Dara Khosrowshahi said that employees will still be allowed to come into offices on a voluntary basis. Staffers who do come in will be required to wear a mask, regardless of their vaccination status.

With the announcement, San Francisco-based Uber is joining a growing number of large tech companies requiring on-site employees to have been vaccinated against Covid-19. Facebook Inc. and Alphabet Inc.’s Google have also issued similar mandates as the number of infections rises.

Uber rival Lyft Inc. said it would postpone its return-to-office date to Feb. 2 and will also require employees be vaccinated.

Business Insider earlier reported Uber’s plans.

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