Recent changelogs

Change Fixed compatibility issue with newer ProtocolLib versions.
Change Minimum supported ProtocolLib version is now 4.4.0. If you have older versions, {player} and {displayname} will not work.

New Added support for Spigot up to 1.16.4.
New Added support for custom colors in hexadecimal format (Example: &#FF87D1), which only work in Spigot 1.16 and higher.
Change Fixed minor bugs.

New The {world: ...} placeholder now supports multiple values. Example: {world: world, world_nether}.
Change Improved performance in some situations.
Change Removed config option precise-hologram-movement, now it's always enabled and doesn't affect perfomance as before.
Change Fixed holograms saving incorrectly after using /hd readImage or /hd readText.
Change Fixed multiple errors related to ProtocolLib.
Change The plugin now requires Spigot (not just CraftBukkit) at startup.
Delete Removed support for Minecraft 1.8.0 (minimum required version is now 1.8.3).

New Added support for Spigot up to 1.15.2.
New Added support for NBT tags in icons. You can add NBT after the icon's material.
Example: ICON: diamond {... NBT data here ...}.
Change Fixed RedisBungee support on 1.13+.

New Added support for Spigot up to 1.14.4.
New Added clickable command suggestions in chat after editing a hologram to quickly edit the lines. Can be disabled in config.yml by setting quick-edit-commands to false.
New Hologram names can now contain uppercase charaters. When referring to holograms by name, they are still case insensitive.
New Re-added RedisBungee support for 1.13+.
Change Plugin now requires Java 8.
Change External plugins still using the old Holographic Displays API (from v1.x) will now cause a warning in the console. In future versions it will raise an exception.
Change (For developers) Player relative placehoders now follow setAllowPlaceholder(...) rules.
Change Touchable holograms now have the hitbox at the correct height.
Change Fixed error related to items with ProtocolLib on older versions.
Change Fixed error related to the stacktrace when using some versions of Java.

Change Fixed {player} and {displayname} not working in some cases.
Change Prevent holograms from being loaded before the worlds when using world management plugins.
Change Fixed pickup handler not working (only used by other plugins through the API).
Change Fixed an error with Protocol Lib temporary players (used by other plugins).
Delete Dropped support for old Protocol Lib versions, now 4.1+ is required.

New Added support for Spigot 1.13 and 1.13.2.
New Added bStats for metrics (https://bstats.org/plugin/bukkit/HolographicDisplays).
New Added option precise-hologram-movement (it prevents lines being misaligned when a hologram is teleported frequently, e.g. plugins that add chat bubbles above players heads with holograms). Disabling the option, if not needed, may slightly improve perfomance.
Change The plugin is now compatible with Java 9 and above.
Change Prevent hoppers from picking up item icons inside holograms.
Change Reading files with commands is now restricted to the plugin's folder.
Change Fixed an error with Protocol Lib.
Delete Dropped support for 1.7.x.
Delete Removed support for RedisBungee in 1.13+ (until RedisBungee supports 1.13).
Delete Removed MCStats for metrics.

New Small performance improvement for all Minecraft versions.
Change Fixed updater messages warning about misconfigured update system.
Change Better error handling for placeholders added by other plugins.
Delete Removed previous performance improvement for 1.11 (it was causing the position of the holograms to be out of sync).

Change Fixed armor stands being shown to players under certain conditions.
Change Attempt to fix slimes not spawning with Silk Spawners and similar plugins.
Change Improved performance on Minecraft 1.11+.
Change Now correctly handles asynchronous chunk loads from other plugins.

Change Fixed disconnect error with ProtocolLib when hiding and showing a hologram to a player.
Change MOTD variable now displays correctly for 1.9+ servers.

New Improved Protocol Lib support, fixed many errors. Compatible Protocol Lib versions based on the server version:
- Minecraft 1.7: versions between 3.6.4 and 3.7.0.
- Minecraft 1.8: versions 3.6.4-3.6.5 or 4.1+.
- Minecraft 1.9 / 1.10: versions 4.0 and higher.
Change The plugin will also check if you have a compatible Protocol Lib version, otherwise it will display a warning on the console.
Change Fixed error with teleport packets in 1.7.10.