They still have nearly 10k employees and are a big, affluent company. None of their project should be a one-man project, but, even if it were, they should still be able to find enough engineers to work on it in case of emergencies.

If it can be done by a small startup with a total of 3 devs in the entire company (and I have seen it done), it can be done by a company the size of Citrix.