There seems to be a bug in the last version (4.3.0) where the button does not appear. I also do not see it. And the Kobold has disappeared entirely. Not that it's a problem for me as I already have most if not all things unlocked... Just saying something to say something. I'm sure the team is already aware of this issue and have already addressed the problem accordingly though. So, see you in the next update ^_^ & thanks for the hotfix!
EDIT: Can confirm. This was immediately fixed in v4.3.1 Recommend installing and unpacking the most recent version for those of you having this issue ;)