8.3 Beta to 8.4 GA upgrade - says I already have latest ver

Hi. I'm not sure I get this problem ... so far as I can tell I can preview email attachments just fine (have tried doc/x and xls/x).

Am running build 5001lf (64 bit) with plugins 8.3.0.5292 (and Windows 8.1/Office 365 (2013)).

K

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