How to update a root certificate

:o this is confusing..

My website:
When I click the green padlock, the first screen 'certificate' shows an expiration date in july 2018.
When I click tab path (I use Chrome), the root has een expiration date in september 2021.
Below that, the certificate has an expiration date in march 2021.

Now I see I can export all 3 of them.
I did export the first one (7-2018), so appearently not the root (though https did work?)

To make things clear: I should export the root (top, 9-2021) certificate, right?