In the haze of excitement over getting the latest and greatest from Android, sometimes we forget that some people actually depend on their phones and tablets for work. Within the professional world, mobile access to email tends to be vital. For better or worse, an overwhelming number of businesses and organizations rely on servers running Microsoft Exchange (or other software implementing the protocol) to handle their email and calendar needs. Unfortunately, a minefield of bugs in KitKat's Exchange support are leaving many stranded without access to their employer's servers.
If you're the corporate type and have had some issues with Android's default Exchange compatibility, then you've probably looked for a good alternative. Among the contenders is an app by NitroDesk called "Exchange By Touchdown," which allows for secure, encrypted Exchange synchronization.