Mojang has been hard at work over the past few days creating games for charity in their annual Mojam livestream. It seems the company is getting back in the swing of things, because today Jeb (the main developer of Minecraft) tweeted, "Minecraft 1.5 will be released in roughly 2 weeks, [in] early March." The update, commonly referred to as the Redstone Update, will add a huge amount of redstone-powered blocks. Some of which including Comparators, Minecarts with TNT/Dispensers/Hoppers/Spawners, Activator Rails, Weighted Pressure Plates, and much more. Updates not related to Redstone include Skeletons and Zombies that are harder to melee and adjust their difficulty, A new texture pack format, new Quartz-related blocks, and more. In a reply to Jeb's tweet asking about the new lighting engine that would remove virtually all lighting bugs, he responded by saying it will not make it to 1.5. You can see the original tweet in the source link below.
Source: Twitter