Onenote2007 notebooks are read-only in Onenote2016 unless I convert them - onenote

Question

I have a stack of onenote2007 notebooks that I'd rather not convert to onenote2016.
Opening one of these onenote2007 notebooks in onenote2016 results in every section being read-only.
I searched the internets and found this article:
https://support.office.com/en-au/article/Upgrade-to-OneNote-2016-for-Windows-d22943e9-4c4e-4b4c-bbeb-2aa533e71ea1
The article says:
OneNote 2016 can read notebooks created with either OneNote 2016 or 2013 and it can also open, view, and edit any notebook files saved in the older OneNote 2010 and 2007 file formats.
If you’re upgrading from OneNote 2007 to OneNote 2016, your existing notebooks in the 2007 format won’t be automatically converted. This is to make sure you can use OneNote 2016 for all the notes you’re currently working in, including collaborative projects with people whose shared notebooks are saved in the older format. If you're still sharing notes with people using OneNote 2007, postpone upgrading the notebook file format until all others have upgraded to OneNote 2010 or later.
So, it sounds like I should be able to edit a onenote2007 notebook in onenote2016. But it shows up as readonly.
Things i've tried
Checked my office2016 is activated.
Tried to open the notebook from a \\ path. Same read only problem.
Tried to open the notebook from a C:\ path. Same read only problem.
Ensured the path to the notebook is not read-only by the OS.
I converted a section of a test notebook to onenote2016 and I could now edit that one section, but not the others (as they hadn't been converted)
I've checked the options for onenote2016 and couldn't find anything.
Thank you in advance.

Answer 1

If you’re upgrading from OneNote 2007 to OneNote 2016, your existing notebooks in the 2007 format won’t be automatically converted. This is to make sure you can use OneNote 2016 for all the notes you’re currently working in, including collaborative projects with people whose shared notebooks are saved in the older format. If you're still sharing notes with people using OneNote 2007, postpone upgrading the notebook file format until all others have upgraded to OneNote 2010 or later.
To check which file format a notebook is saved in:
In OneNote 2016, open a notebook, and look at the title bar of the OneNote window. If [Compatibility Mode] is shown next to the notebook name, then the notebook is saved in the older 2007 format.
In OneNote 2010, choose File > Info. Next to the name of the notebook you want to check, choose the Settings button, and then choose Properties. In the Notebook Properties dialog box, look at the Default Format to see what format the notebook is saved in.
Guess you'll have to export each files by hand to the 2016 format :/
From : https://support.office.com/en-us/article/File-format-changes-in-OneNote-2016-for-Windows-a9129622-1755-470b-91e7-b2a461194036

Answer 2

I upgraded OneNote 2007 to OneNote 2016 and this is how i fixed it.
Right click on the notebook.
Select Properties
Select the button that says "Convert to 2010-2016"
Done!
Thanks!