With free version, you can only enter your data up to 15 on each month.
Let's say, today is March 25, 2018 and you want to enter a lot of data for 2017. In this case, you can enter 14 entries on January 2017, 13 entries on February 2017, and so on for free. But, you need to subscribe to Taxnote Plus when you want to enter more than 15 entries on March 2017.
*You need to buy Taxnote Plus for each when you use iOS and Android both, even though you can share Taxnote Cloud account on iOS and Android devices.