23w15a: Olden Days Update

23w15a, aka Olden Days Update, is a snapshot for 1.21: Underwater Ashes Update.
== Additions ==
=== Lava Bottle ===
* Places still lava, just like the still lava item.
* Obtained by dropping a glass bottle on lava.
=== Milk Bottle ===
* New item.
* Clears all negative status effects.
* Obtained by using 2 milk buckets then glass bottles.
* Stackable.
=== Specific Cheats ===
* Allows the player to enable specific commands such as /publish, /modifyitem, /acquire.
== Changes ==
=== Cauldron ===
* Accidentally removed direct item forms of cauldrons.
* Direct transmutation no longer works with cauldrons.
=== Blaze Powder ===
* Can no longer craft eyes of ender. Eyes of ender are crafted with 6 aluminum plates and 2 ender pearls.
* Can now be obtained through liquid flames of blazes.
=== Fermented Spider Eye ===
* Fermented spider eyes can now corrupt the potion of Slowness, Harming, Poison and Wither, turning them into potions of Swiftness, Healing, Regeneration and Health Boost.
=== Glass Bottle ===
* Can now be filled with lava and milk.
* To fill a glass bottle with milk, the player must use a milk bucket first and then a glass bottle, replenishing the milk from the bucket and bottle.
=== Magma Cream ===
* Is now dropped by magma blocks with a 21% chance.
=== strad ===
* Strad music discs are now sold by electrician villagers.
* Strad music discs are now crafted with 8 aluminum plates and 1 iron ingot.
=== Spider Eye ===
* Now has a 85% chance to drop from spiders, rather than 33% or 67%.
=== Breeding ===
* Sheep can now breed with themselves (mutton).
=== Hardcore ===
* Health now regenerates at a rate of half a heart per 5 minutes.
* Specific Cheats can now be enabled in Hardcore mode.
===Achievements===
*Renamed to advancements and made customisable once again. Prior to that, achievements were completely hardcoded.