If you find any bugs or typos you can submit and keep track of them directly on the developers' Trello board here: https://trello.com/b/ABG1gSZb/need-to-know-bugs-feature-requests. I've submitted a bug and a typo and they should be fixed in the next release :)

As for the changelog, if you're not using Galaxy, you can visit your account, open up Need to Know in your account, click on the "More" section and that will show you a dropdown menu. Select "Changelog" from the dropdown menu and you will see all of the game's available changelogs.

If you're using Galaxy, just click on the version number and you will get a pop up window with the changelog.