 In November 1998 work on Netscape 5.0 was cancelled in favor of developing a completely new program from scratch.Netscape 5.0 (codenamed "Gromit") was a continuation of the 4.x code, but only two pre-alpha versions were written, one based on original Communicator code (with layout engine stability and performance enhancements to the 4.0 codebase, codenamed Mariner) and another using the Gecko layout engine.Though Netscape had originally intended to deploy Mariner and later replace it with Gecko (which had been developed from scratch), Netscape 5 and Mariner were scrapped completely.