The 2k base coat & solids are being phased out due to nasty VOC, or volatile organic compounds.
In future you will need to use water based base coat & 2k clear laquer. There is less VOC in the laquer.
There seems to still be plenty of 2k base & solids around. Most stuff bought in has 2006 stamped in it. Now this is either old stock or a sticker to cover their ass!