|Outlook Client Version Report|
If you find that you need to upgrade clients to a new version of Office, I recommend that you install the x86 version of Office to provide the best compatibility with add-ons and third-party products. Some customers think they need to install Office x64 on Windows x64 operating systems, but that's not the case. See 64-bit editions of Office 2013 for details on when it makes sense to install Office x64.
If you're an Office 365 customer, I strongly recommend checking out using the Office 2013 ProPlus software deployment that's most likely part of your Enterprise license. This version of Office 2013 can be installed on up to 5 PCs, iPads, tablets, etc. and is always up-to-date since it's a cloud-managed service.