Find more information on ZDoom forum.ZDoom 2.6.0 changelog: wrote:Added Hacx IWAD support.
Added text-format Strife conversation system with USDF and ZSDF.
A textured automap is now available; automap graphics are now externalized.
Rewritten menu system, which can now be defined with the MENUDEF lump.
Externalized intermissions to MAPINFO.
Externalized IWAD detection and gave each IWAD its own independent config section.
Added FluidSynth and GUS emulator softsynths; fixed issues with TiMidity++.
Added VOC support and enhanced MIDI playback with support for alternative formats such as XMI and HMI.
Action specials: Added Ceiling_LowerAndCrushDist and Thing_SetConversation. Added console command to execute specials.
Increased maximum script number from 999 to 32767.
Named scripts allow to avoid script number conflicts altogether.
Added StrCopy, CheckSight, SetActivator, SetPointer functions.
Added APROP_ScaleX/Y and APROP_Mass actor properties.
Added temporary dynamic strings variables with StrParam.
Scripts can now have up to four parameters.
Added A_CheckFlag, A_FaceMaster, A_FaceTracer, A_RadiusGive, A_SetMass, A_SetScale, A_Warp and A_WolfAttack...
Enhanced A_AlertMonsters, A_BFGSpray, A_Blast, A_CustomBulletAttack, A_FireBullets, A_GunFlash, A_PainAttack, A_RadiusThrust...
Added an actor pointer manipulation system with several new codepointers...
Added DOHARMSPECIES, DONTCORPSE, SEEINVISIBLE and INVENTORY.UNTOSSABLE
Increased damage type flexibility in several ways with DeathType and PainType.
Added customizable fléchettes.
Made accuracy and stamina accessible through DECORATE expressions.
Added ProjectileKickback, Inventory.RestrictedTo and Inventory.ForbiddenTo class-based properties.
Backported VisibleToTeam, VisibleToPlayerClass and weapon DropItem feature from Skulltag, and enhanced them.
Added "Fast" keyword for states and deprecated the unreliable FASTER and FASTMELEE flags.
Added a secret hint system.
3D floors support.
SBARINFO: Ammo 1/2 capacities added to DrawNumber, support for color names in colored text.
SNDINFO: Added musicalias and attenuation.
Compatibility: fixed issues with Eternal Doom, Happy Time Circus, Phobos, vanilla compat, Boom compat, light levels higher than 255, Heretic, Strife, MUSINFO, misnamed UDMF field.
Fixed loading of BMF palettes.
restart console command.
Added PALVERS lump for specifying alternate graphics to use with a paletted render, in case the graphics you really want to use look bad without true color.
Custom IWADs no longer need to include a COLORMAP, as ZDoom will generate one automatically if it is missing.
Fixed vertical tiling of non-power-of-two textures.
It's available on our download page or ZDoom download page.