Signature color change was not supported even in earlier versions of the App. It looks like you are instead referring to the freeform drawing tool. You can still do the same by going into Comment (via the FAB button circular blue button) and then selecting pencil tool from there.
No, I have been using this app for years and updating each time it comes out. After you place the signature you can highlight it and get two options. One to delete and the other to change color. Please provide this feature back into the app.