Different vintages of CLO have different structures, with each successive generation of deals tending to bolt additional features onto an already complex product.
CLOs are not standardised products. They share many features with each other but there are a small differences between almost any two deals, even of the same vintage.
CLOs launched since 2009, when the market re-emerged from the financial crisis, are often referred to as CLO 2.0s and older deals as CLO 1.0s. The difference between the two products has eroded over time, but CLO 2.0s remain distinct from older deals in several key respects.