Apple released a new capability in IOS 8 that allows the user to replace their phone's keyboard with an alternative provided by a third party.
Applications like these can also replace the calendar functions on a phone as well as its contact functions.
When these apps are installed, the user gives permission to third parties (the developer of the app) access to their device. If it's a keyboard, that developer can convievably see anything that you type (like passwords, account numbers, or confidential information); like your calendar (which you may presume is private); or your contact list (who may not appreciate you sharing their information).
If you are subject to federal or state restrictions over classified forms of information (like HIPAA, GLB, or transferring social security numbers or drivers licenses), it's absolutely vital that you do not install these kinds of applications on your mobile device when working with your business account for mail, contacts, calendar, or drive. Just don't do it. Don't install these applications. There's no guarantee of privacy if there's a middle man between you and your data.
if you're at all concerned about privacy and security, just don't do it. Don't install these applications.
if you use your device to take credit cards for your business, please - for the love of everything holy - do not install these applications.
If you do use these applications, bear in mind that the licensing agreement for use may stipulate what those third parties do with their access to your data. You may want to read those end user license agreements, usually found within the app or on the developer's website.
And if you have any questions, please feel free to reach out to me. I may be able to help coach you through your options. Thanks.