Before we get into the update
I wish to specifically praise @stumper66 and @Oathkeeper for their immense generosity in delivering LevelledMobs 3 to the community. They spent days on end to get everything ironed out as much as possible so that server owners can drag and drop it in and enjoy the brilliant changes that they have designed, implemented and tested.
Here is a link to donate to stumper66, if you wish to give him your thanks for his vast efforts of getting LM v3 released. Oath doesn't have a donation link, but you could send him a nice PM with your thanks. Cheers!


Alright- let's get into the update!

A new LevelledMobs Era has begun
We have enhanced LevelledMobs with an entirely new Rules System!
This system adds a significant level of depth and complexity to the plugin which required months combing through the core programming; tightening the resource management and debugging options, crafting many new features and expanding old ones, all while taking the time to craft highly detailed configurations and test dozens of BETA-builds prior to release to ensure the final product is perfect and the transition from LM2.X to LM3.X, while significant, will hopefully be as seamless as possible. At the very least, our Support Discord will be happy to provide the fastest support to get your server running with the latest, greatest version of LevelledMobs!​

README: Important
With the change to LM3.X, so much has been recreated that the Migrator which would typically transfer your settings over from update to update will not function during this transition. It will still create the .OLD file backups, however the newly generated files will be using DEFAULT settings for most configs.

NEW Default Values!
While most of the default values from LM2.X to LM3.X have either remained the same or very similar, a handful have been altered thanks to years of play-testing and suggestions from the community! The prior versions of LevelledMobs were built to be an above-average challenge under NORMAL difficulty for a very-small server community. With LevelledMobs’ popularity with so many larger sized servers, that meant that the default configurations were becoming inadequate as more features were introduced. Our goal now is to challenge a properly equipped and enchanted player on Hard difficulty, while demonstrating a proper spread of health, damage, and movement-speed. Below are a few of the major changes to note, and a description of why:

• New Min/Max Level of 1-50, changed from 1-10
• Overworld and Nether use new Levelling Strategies (Blended and Y-Coordinate)
• New Multiplier Value and System (Level-Up Attributes)

With significant play testing, it was determined that the Blended levelling would work best as the new default for the Overworld, while the Y-Coordinate levelling introduced in LM2.X would work best for the Nether, each combined with the new default level range of 1-50, which best demonstrates both levelling strategies in their native environment over an expanded range!
We also found the need to adjust the multiplier attributes to fit with the new scope. While there is not an easy to quantify difference.
At maxLevel; the formula for:

Attributes: finalValue = ( vanillaAttribute x configValue ) x (( entityLevel - 1) / maxLevel )

Drops: finalValue = vanillaDrop + ( vanillaDrop x configValue x (( entityLevel - 1) / maxLevel ))​

• MAX-HEALTH has changed from roughly 2.0x to exactly 3.5x vanilla.
• MOVEMENT-SPEED has changed from roughly 0.25x to exactly 0.3x vanilla.
• ATTACK-DAMAGE has changed from roughly 2.0x to exactly 2.75x vanilla.
• RANGED-ATTACK-DAMAGE has changed from roughly 1.0x to exactly 3.0x vanilla.

NEW Modular Rules System!
The core change to LevelledMobs comes in the form of the new Custom Rules system!

Applied in linear order, from the Default-Rule to the first-thru-last listed Custom Rules, you now have complete control over the LevelledMobs system. Select the conditions to check, then utilize one of many strategies to determine the entity’s level, and finally apply-settings from custom min/max values, unique multipliers, and more! For the most detailed description of how to use each and every setting, read the documentation included in your RULES.YML file!

• Default Rule
  This section of the new Rules system is required for LM to function! This tells LevelledMobs what settings to apply to any entity which has not been further defined within the Custom Rules. Most Conditions, Strategies, and Apply-Settings can be defined here.
  
  
• Custom Rules
  Here within the Custom Rules system you can define exceptions or alterations to the Default Rules which can be enabled or disabled when they’re needed.

NEW Spigot 1.17 & Progress to Compatibility!
LevelledMobs has been for the most part updated to support the latest release of Minecraft compiled through Spigot! We are still waiting on an update for ProtocolLib, which handles the nametag features. Once this is done, all should be good with 1.17 support!​

NEW CustomDrops Features!
Many new features have been included into CustomDrops as well! This includes checking whether an entity’s death was player-caused, more detailed overall chance system, and the ability to drop PLAYER_HEAD blocks!​

NEW Custom Command Drops!
Alongside the new CustomDrops features, we introduce the ability to ‘drop’ commands as a reward for entity deaths. We also included customized %ranged% tags for random command elements, providing even further variance to rewards without requiring multiple instances of the same command.

NEW Blended Levelling System!
A long time goal of LevelledMobs! We have finally introduced the ability to merge Y-Coord levelling and Spawn-Distance levelling within it’s own structure called ‘Blended’. By default, this system will use the Spawn-Distance levelling strategy, and then modify the level based on it’s Y-coordinate when spawned. The level will decrease as climb mountains, and increase as you go mining for diamonds underground.​

NEW Biome Specific Levelling!
Also long requested, the ability to make level specifications based on the biome where the entity spawned! It works no differently than specifying the world, so it’s simple to use! And it also comes pre-built with several Biome Groups, which contain groups of biomes collected together based on climate!

NEW Custom Mob Groups!
First we only had ‘Universal Mob Groups’, now we also have ‘Custom Mob Groups’, where you can define sets of entities which can later be used as a Group when defining new Rules.​

NEW Deeper WorldGuard Region Integration!
You can now utilize WorldGuard regions within the new Rules system, which allows you to specify all Levelling rules within the confines of a region, rather than simply the old system of a few flags and a handshake!​

NEW Stronger MythicMobs Integration!
With the new ‘mythicmobs-internal-names:’ configuration option, you can further specify MythicMobs by their internal name instead of ALL or NOTHING when enabling the plugin!

NEW Dynamic vs. Static Attributes!
In the past, we used a static attributes file which contained the default values for every entity in Minecraft, which was referenced when generating the attributes for entities. This resulted in cookie-cutter copies of the same entity across the same level regardless of situation or in-game variance. After lots of effort we have transitioned the system to grab the attributes from the entity itself as it spawns, allowing for any variances which are applied before LevelledMobs gets it’s hands on it. We left the option to use the original static attributes system within SETTINGS.YML just incase your server arrangement necessitates it!​

NEW PlaceholderAPI (PAPI) Support!
Requested by the community, we’ve included limited PAPI support for the %level% and %displayname% of entities. You can download PAPI at https://www.spigotmc.org/resources/placeholderapi.6245/​