The official name for the update, the Combat Update, was discovered on April 1, 2015 by Reddit user 3dDeters (and several others independently) who found a QR code hidden in the snow falling pattern of the April Fools 15w14a snapshot.
Development on the Combat Update began at least a month before the Bountiful Update was released. The development period was over twice as long as the development period for 1.8 at 576 days; 2015 became the first year where a major update to Minecraft was not released. Snapshots began the day after 1.8.8 was released. 56 development snapshots were released, from 15w31a to 16w07b, making it the update with the most snapshots so far. The time between releases of 1.8 and 1.9 represent the longest time span between major updates, at 545 days. Fifteen iterations of the launcher were released during this period, from 1.5.2 to 1.6.59. 1.8.9 was also released during this period.
The development team called the release feature-complete by the end of October 2015, and started a lengthy period of gameplay balancing and bug-fixing. They later announced that 1.9 would not be released in 2015, as the developers "want to fix more bugs before release, and keep the game stable over the holidays".
Mojang released the first pre-release on February 17, 2016. The date for this was hinted at by the image in the blog post that announced snapshot 16w06a. The data values of the wool in the image were (1, 7, 0, 2, 2, 0, 1, 6), having a possible (though never confirmed) interpretation of "17-02-2016", a date just one week from 16w06a. The second pre-release was released on February 18th, the third pre-release was released on February 24th, and the fourth pre-release was released on February 26th.
- Method of restarting the ender dragon boss fight
- Infinite generation of islands in the end, populated by chorus trees, end city structures and ships, and shulker mob
- Attack strength mechanic
- Attribute system
- Shield, spectral arrow, 14 types of tipped arrow and a lingering potion for each type of potion.
- Elytra for flying
- Off-hand slot, and dominant hand option
- Igloo structures that generate in cold biomes
- Skeleton trap horses that spawn during thunderstorms.
- 13 new blocks: grass path, frosted ice, 2 new types of command block, chorus flower and plant, end gateway block, end rod, end stone brick, purpur block, pillar, slab and stairs.
- New items: beetroot with seeds and soup, end crystal, normal and popped chorus fruit, luck potion and dragon's breath
- 5 new splashes.
- 4 new particles:
- 4 new status effects:
- 4 new statistics
- Lots of new NBT tags
- 1 new gamerule
- 150+ new sound events
- Support for Chinese, Japanese and Korean, and probably other IME entered languages
- Changed the layout of the end island pillars and the ender dragon boss fight.
- Skeleton AI is more difficult.
- Sword blocking removed, and several other weapon techniques added.
- Tool damage is rebalanced.
- Sharpness and protection enchantments are nerfed.
- Status effect icons are now visible on the main screen.
- Health regeneration is rebalanced.
- Fishing is rebalanced.
- Brewing stands now require blaze powder.
- Enchanted golden apples are no longer craftable.
- Maps changed.
- Loot found in chests generated in the world is rebalanced.
- Death in hardcore mode allows the player to continue in spectator mode.
- Boats are improved.
- Stronghold generation increased to a maximum of 128 strongholds.
- Large oak trees generate in forests again.
- Increased fire spread while raining.
- Glass panes and iron bars have a thin appearance when not connected, as opposed to a crosslike appearance.
- Mobs and players now push one another around.
- Death message is now displayed on the death screen.
- Mob and player heights are slightly modified.
- Resource packs can specify models depending on damage value, item state, and hand.
- Structure data now comes from /assets/structures.
- Loot from mobs, fishing and chests is now determined by loot tables.
- Particles are no longer entities
- Block ticking
- Mob pathfinding
- Memory usage when connected to servers
- Chunk generation, loading and sending
- “We've updated the release date for Minecraft 1.9 to February 29! Why? Because it's Leap Day!” – @jeb_, 2016年2月23日
- “Darn, I hoped this would go unnoticed for a few days. Well spotted, @3ddeters. http://www.reddit.com/r/Minecraft/co …” – @Dinnerbone, 2015年4月1日
- “@MushirMickeyJoe @erismetis We started working on 1.9 before we released 1.8. Therefore, "1.9 started" minus "1.8 released" is negative! :D” – @Dinnerbone, 2015年10月15日
- “@MushirMickeyJoe @JordanFisher_YT Negative month or two. We started working on 1.9 long before we released the first snapshot.” – @Dinnerbone, 2015年10月15日
- “We are aiming to get Minecraft 1.9 feature complete at end of this month. Feature complete doesn't mean bug free & ready to release, though!” – @Dinnerbone, 2015年10月15日
- “Update: Minecraft 1.9 will not be released this year. We want to fix more bugs before release, and keep the game stable over the holidays” – @jeb_, 2015年11月24日