This first generation Ultegra Di2 Front Deraileur can be used on 2x10 Di2 builds. Note that it will not work on triple setups.
It is meant to be used with a chain line of 43.5mm. Recommended top gear teeth range is 50-56T and its total capacity is 16T
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Originally this derailleur could be used together with an 11-speed rear derailleur, but that functionality was later removed in a firmware update. You can not longer use different speed derailleurs on the same bike.
If you are using one of these with an 11 speed rear derailleur I strongly recommend you do not update its firmware.
What is a rear derailleur's total capacity, really? Why is there a top sprocket minimum? And what about front derailleurs? Chain line, total capacity, Top gear teeth? This page explains all of those, and more.