The absolute earliest it will happen is the Legislative session in 2017.
If it does not happen then, well, add 2 years to 2019.
Knife Rights came close this past session to getting it done, but close only counts with horse shoes, hand grenades and thermo-nuclear devices.
Every session is both different and the same. Next session, it may be a piece of cake or it may be a political football. A lot will depend on everything else that happens over the next 2 years - who get elected/re-elected, i.e., President, Governor, Lt Gov, House and Senate members, events that occur between now and then. Lots of uncontrollable, unknowable and unpredictable events/situations.
It took 2 tries to get the pre-emption bill passed. It took 5 or 6 sessions to get concealed carry passed. Took a couple of sessions to get open carry passed after a few years of CC. This session was the first major attempt at significant knife law reform in Texas since Reconstruction. Politicians are like mules - stubborn, set in their ways and sometimes you gotta hit'em with a 2x4 to get their attention. Patience wins out.