Honda has research lean burn engines for decades. I suspect that it is much more involved than a software change. Any engine can be adjusted lean. Doing so dramatically raises NO2, will cause you to fail emissions testing, void your warranty, castrate your cars performance, and may damage your engine. Therefore, (as Rick mentioned), we cannot discuss this here.
However, there are many tips that apply to CVT engines as well as 5 speeds. The biggest gains are achieved through practice and technique as well as simple things like extra pressure in the tires, synthetic oil etc.... This was demonstrated by hypermillers who went off the scale at Hybridfest achieving double EPA in both Prii and Insights. (You may wish to contact one of the winners directly.)
Congratulations on your purchase and welcome to the forum.