In this snapshot we made some changes to Redstone wire and we fixed a bunch of bugs.

Changes in 20w18a

Redstone wire changes
The target block now conducts redstone signals

Redstone wire

The blockstate, rendering and behavior of redstonewire are more in line with each other. Redstone will provide power to blocks on all sides it shows a visual connection to, and not do so on those sides without a visual connection.

A single redstone wire is now represented as a cross.
A wire on top of a block, which is redirected from below, will power the sides it is redirected to now. E.g. a fence gate above the redirecting wire will be powered.
Wires that redirect upwards to wires on non-conductive blocks used to only be redirected visually. Now this redirection applies to their behavior as well.
A wire that is redirected to go over a block will now always provide power to the block. This is most noticeable when the wire has signal strength 1.

Comparison between 1.15.2 and snapshot 20w18a

Technical Changes in 20w18a

Added a enable-status option to the server.properties file which if set to false will suppress replies to status requests from clients. This makes the server appear offline in the multiplayer screen.
Added control over how much entity data a server sends to clients
Advancement system changes

Entity Broadcasting

It is now possible to control at what range the server sends data about entities to clients.

Added an entity-broadcast-range-percentage server property controlling how close entities need to be before being sent to clients. Higher values means entities are visible further away from players but cause more network traffic. Specifies percentage of default value, so for example 50 specifies half of the default range.

Advancements

Added player check to every trigger (except impossible)
Entity checks in triggers can now use loot table condition syntax

Extended entity checks

Entity checks in triggers can now use loot table condition syntax. Old notation:

{
  "trigger": "minecraft:player_killed_entity",
  "conditions": {
    "entity": {
      "type": "minecraft:blaze"
    }
  }
}

is now equivalent to:

{
  "trigger": "minecraft:player_killed_entity",
  "conditions": {
    "entity": [
      {
        "condition": "minecraft:entity_properties",
        "predicate": {
          "type": "minecraft:blaze"
        },
        "entity": "this"
      }
    ]
  }
}

Note 1: Like in loot tables, all conditions in top level array must be met for whole condition to trigger. Note 2: To access new functionality, top level element must be JSON array. JSON object are interpreted as old notation.
Full list of extended triggers:

New field player in every trigger
bred_animals - parent, partner, child
channeled_lightning - victims
cured_zombie_villager - zombie, villager
fishing_rod_hooked - entity
killed_by_crossbow - victims
player_killed_entity - entity
entity_killed_player - entity
player_hurt_entity - entity
summoned_entity - entity
tame_animal - entity
target_hit - projectile
villager_trade - villager

Miscellaneous trigger changes

Due to addition of player, existing contents of location, slept_in_bed, hero_of_the_village, voluntary_exile can now be placed in location field instead of top-level object. Old syntax is still supported, but depreciated.

Fixed bugs in 20w18a

MC-11211 Unable to perform many right click actions when targeting the top face of blocks placed at y=255
MC-111381 Rendering rotations for shulkers are set in onInitialSpawn method
MC-143904 Adding a non-rail block to the "rails" block tag will crash the game when placing a minecart on it
MC-147255 Beds in the overworld will explode if in a nether wastes biome
MC-162385 The background of the title text does not fade with the text
MC-166269 Wet wolves become black for an instant after shaking off water
MC-166296 Mobs picking up and equipping items does not play the equipping sound
MC-170840 Broken spawn rates in soul sand valleys and warped forests
MC-170944 /locatebiome messages do not fit for all biome names
MC-171523 Inconsistent strings for warped and crimson wall signs
MC-172172 Adult piglins spin around while following the player
MC-172253 Equip sound doesn't play when Piglins equip items
MC-173067 NullPointerException when a structure containing a campfire is placed during world generation
MC-173198 Target blocks are transparent and do not transfer redstone signals
MC-173385 New Nether lighting system doesn't affect fluids, entity-like blocks (chests, etc.) and entities
MC-173747 Armor enchantment glint doesn't render
MC-174573 Nether vines can drop multiple copies with fortune (free duplication)
MC-174593 Inconsistent pluralisation in "fell off a scaffolding"
MC-174811 Zombified piglins are able to spawn on top of nether wart blocks
MC-175107 It's possible to get Bad Omen VI in Survival mode
MC-175740 Game crashes when dispenser is used on non-beehive block in #beehives tag
MC-175741 Game crashes when a cat attempts to sleep in a non-bed in the #beds tag
MC-176028 Striders can spawn in stacks of three or more
MC-176032 Striders can float
MC-176135 Striders riding other entities are not cold
MC-176203 Striders with Levitation walking on Lava don't levitate
MC-176459 Baby striders can spawn with saddles
MC-176468 Adult striders can spawn with saddles
MC-177105 Piglins, hoglins, zoglins and villagers look at their target's feet instead of its head
MC-177127 Unnecessary exclamation point in subtitle "End Portal opens!"
MC-177173 Baby Zoglin age status value is not stored in the NBT tag.
MC-177561 Compasses used on the top of lodestone at y=255 do not break when the lodestone is destroyed
MC-177771 "death.attack.fireworks.item" displays raw translation string (is untranslated)
MC-177790 Piglin Banners are named block.minecraft.banner.piglin.[]
MC-177794 Globe Banner Pattern is not required to add the globe to a banner
MC-177816 Failed to access/delete level should be "world"
MC-177911 Cave generator doesn't cut through blackstone
MC-177951 Game crashes when fire starters are used on a non-campfire in the #campfires tag
MC-177976 Baby piglins can pick up soul campfires
MC-178013 Zombified Piglins riding striders can despawn, leaving saddled striders
MC-178129 Entity conversion subtitles use inconsistent tenses
MC-178336 The message "You have no home bed or respawn anchor, or it was obstructed" doesn't make it clear that your respawn anchor might have been depleted
MC-178817 "Chain Blocks" don't have a "waterlogged" state
MC-178943 Piglins/hoglins spawned in bastion remnants can outrun players
MC-178949 Bastion Remnants cannot be generated in in superflat worlds
MC-179839 Chat text renders behind the armor bar
MC-179841 Game crashes when you optimize your world
MC-179845 Rain falls through any blocks in some spots
MC-179847 Hoglins and Piglins spin around
MC-179850 There is no difference between Entity Distance 100% and 500%
MC-179858 Maps show stone-like pattern despite it not being there
MC-179863 Setting attribute minecraft:generic.max_health value to 0 or lower causes an infinite death loop after dying
MC-179866 In some spots, it is raining even if it should be snowing
MC-179868 Crash when going to a previous page of writable books
MC-179883 Raw JSON text duplicates components in "extra" in entity names
MC-179886 Play button overlay doesn't appear in worldsave selection GUI
MC-179905 Caption of game rule screen is missing
MC-179952 Height map data doesn't get converted
MC-179954 Keybindings are not correctly inserted into the demo info box text
MC-180030 Adult hoglins zombified into an adult zoglin deals the same damage as a baby
MC-180100 Rain particles appear black under certain conditions
MC-180110 Underline and strikethrough in JSON text don't always render correctly
MC-180125 Incorrect font spacing on non-BMP characters
MC-180135 Empty chat messages are not displayed
MC-180138 Long messages in chat no longer have hanging indention
MC-180246 The "r" in "Game rules" is not capitalized
MC-180248 The "g" in "Upgrade gear" is not capitalized
MC-180299 "Elytra" in "Disable Elytra movement check" is inconsistently capitalized
MC-180353 Chat background renders in front of the Debug Menu but chat text renders behind it
MC-181296 Panorama has wrong overlay when using Programmer Art

Minecraft Snapshot 20w18a