The data portion of this binary package uses a deprecated compression format. Although dpkg will support extracting such binary packages for the foreseeable future, creating them will eventually be disallowed. A warning is emitted for lzma since dpkg 1.16.4, and for bzip2 since dpkg 1.17.7.
For lzma, xz is the direct replacement. For bzip2 either gzip or xz can be used as a substitute, depending on the wanted properties: gzip for maximum compatibility and speed, and xz for maximum compression ratio.