**For Minecraft: Bedrock Edition 1.19.70**

### Note about API versions
Plugins which don't touch the `pocketmine\network\mcpe` namespace are compatible with any previous 4.x.y version will also run on these releases and do not need API bumps.
Plugin developers should **only** update their required API to this version if you need the changes in this build.

**WARNING: If your plugin uses the `pocketmine\network\mcpe` namespace, you're not shielded by API change constraints.**
Consider using the `mcpe-protocol` directive in `plugin.yml` as a constraint if you're using packets directly.

### Alpha release warning
Alpha releases are **experimental**. Features introduced in these releases are subject to change or removal.

APIs which existed **prior** to this version will continue to work as normal, so plugins which use them will continue to work.

### Highlights
This version makes changes to the internal network system to improve server performance and reduce memory usage.

While these changes don't affect non-internal API, they are still significant enough to warrant a new minor version, as they may break plugins which use the internal network API (not recommended).

# 4.18.0-ALPHA1
Released 16th March 2023.

## General
- Improved server performance in congested areas of the world (lots of players and/or entities in the same area).

## API
### `pocketmine\event\server`
- The following new classes have been added:
  - `DataPacketDecodeEvent` - called before a packet is decoded by a `NetworkSession`; useful to mitigate DoS attacks if PocketMine-MP hasn't been patched against new bugs yet

## Internals
- Introduced new system for broadcasting entity events to network sessions.
  - This change improves performance when lots of players and/or entities are in the same area.
  - New interface `EntityEventBroadcaster` and class `StandardEntityEventBroadcaster` have been added to implement this.
  - All entity-specific `on*()` and `sync*()` methods have been removed from `NetworkSession` (BC break).
  - `NetworkSession` now accepts an `EntityEventBroadcaster` instance in its constructor.
  - `NetworkBroadcastUtils::broadcastEntityEvent()` can be used to efficiently broadcast events to unique broadcasters shared by several network sessions.
- All network sessions now share the same `PacketSerializerContext` and `PacketBroadcaster` by default.
  - Previously, every session had its own context, meaning that broadcast optimisations were not used, causing significant performance losses compared to 3.x.
  - This change improves performance in congested areas by allowing reuse of previously encoded packet buffers for all sessions sharing the same context.
  - Packet broadcasts are automatically encoded separately per unique `PacketSerializerContext` instance. This allows, for example, a multi-version fork to have a separate context for each protocol version, to ensure maximum broadcast efficiency while encoding different packets for different versions.
  - `PacketSerializerContext` is now passed in `NetworkSession::__construct()`, instead of being created by the session.
- `StandardPacketBroadcaster` is now locked to a single `PacketSerializer` context, reducing complexity.
- Introduced `NetworkBroadcastUtils::broadcastPackets()`, replacing `Server->broadcastPackets()`.
- `Server->broadcastPackets()` has been deprecated. It will be removed in a future version.