Following its first disappointing holiday sales numbers since its coffee machines hit shelves, Keurig will bring back refillable K-Cups. So far, the Keurig 2.0 machines haven't taken off like the company thought they would, partially because new brewers don't allow users to add their own beans with a so-called My K-Cup filter. The machine -- capable of brewing more than one cup at a time -- also costs $200 while other Keurig options have price tags around $100. In an attempt to revive interest, a version of the My K-Cup for the pricier new brewers is in the works. CEO Brian Kelley said on an investor call this week that Keurig "underestimated the passion" customers had for the DIY option. What about the unpopular DRM requirement that nixed some third-party pre-filled pods? It's staying. The company wants to convert all unlicensed cup to official products, adding to the 500 varieties of coffee, tea and hot chocolate from 70 brands.