I just contacted Abena headquarters in regards to plastic backed 4163 M4.
I sent them this link and they responded:
"I just want to inform you, that this product has been taken out of our product range, so it is not going to be available in the nearest future."
"We still have this product on stock, so it will be available for a period, but we will stop production of this item."
Are they bluffing, or is this true? Bloody Abena...