When did blueberry inserts change?

I was just wondering. I bought last week a fitted side snap blueberry that appeared almost brand new with insert and the insert is 3layers of microfibre with hemp.
The original ones I have have a slightly different insert. It is definitely 2 layers of microfibre with hemp and feels thinner.
They have different colour blueberry labels stitched into them too.

Does anyone know when the inserts changed? Its not very important I just pondering and thought some nappy brain out there might know..

I have a blueberry I bought about a month ago, and some I bought 2 years ago and inserts are all the same, though some have difference coloured labels. so if they've changed it's over 2 years ago!

I've got three large red labelled ones here out of the wash. Two of them definitely only have 2 layers of microfibre and one has three.
I bought some larges new for ds an I think that was a year ago and they have the two layers. I wonder if they were old stock?

I think I've got others with a green(or blue label) but they must be in the nappy bucket.