Patch 1.5 changed the way archery damage is calculated, allowing arrows to benefit from perks/skill/enchants instead of adding a flat amount of damage. Among other things, this change http://www.gamesas.com/topic/1364580-did-bound-bow-get-massively-better-in-15/page__st__30 allowing it to do viable damage on master without needing you to fill every available equipment slot with maxed fortify archery enchants.

1.6 is "fixing an issue" with the way archery damage is calculated. I've searched extensively but have not seen anything discussing whether this means "archery damage is now reverted back to how it was before 1.5," or "we're fixing the tooltip display" (which was incorrect in 1.5). Anyone tested this yet, and/or stumbled across some test results somewhere?

You should probably post this in the forum for the http://www.gamesas.com/forum/186-beta-update-on-steam/

I think it's changeing the way the damage calculaton is shown in the menu.
I don't think 1.5 changed the actual damage,just the way it was shown.

In other words it's fixing it.