Valve's proprietary Source Engine is getting up in years, and the company hasn't seemed eager to replace it. But a few files reportedly buried in the Source Filmmaker imply that perhaps a new iteration of Source is on the way after all.
Valve Time reports that the script files for Filmmaker contain more than 60 references to Source 2. One references to "current engine version" and "next-gen 'Source 2'" in particular. A user also pointed out Source 2 tool icons in the SFM files.
Obviously, this information hasn't been confirmed by Valve, so take it with a grain of salt. Last year the company noted that it prefers to update its existing engine, rather than put the work into a full overhaul. Shacknews has contacted Valve regarding the report and will update as more information becomes available.