Hi Augistinc1913,

The exchange online feature is available in 5.2 version. Kindly check out the link below

https://help.nintex.com/en-US/k2five/userguide/5.2/default.htm#K2-Management-Site/Features/Features.htm%3FTocPath%3DAdminister%7CK2%2520Management%7CFeatures%7C_____0

Should you feel that this post is of use and or an accurate solution to the raised question, I kindly encourage you to mark it as such 
using the 'Best Answer', 'Like' andor ‘Me Too’ options.

Cheers,
Kate

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