Well well well, another release! This time we're fixing more bugs from the recent big 15.3.0 release, but don't think that's all.
We've added loads of requested and useful features this release and allow even more customization. Here's a TL;DR of what's new:

• Fixed refreshing on proxies due to broken protocol
• Cooldown storage, cooldowns are now stored in the file/MySQL storage
• Skin favourites! You can now favourite skins as a player and have SkinsRestorer store them for you. You can either favourite your current skin by doing /skin favourite or by shift + left clicking a skin in the GUI.
• New GUI menu with an overview page that lets you select subpages
  • Skin Menu subpage: The normal menu as you know it
  • History Menu subpage: Skins you've previously used
  • Favourites Menu subpage: Skins you've favourited through /skin favourite or shift + clicking a skin in the gui
• /skin favourites & /skin history list commands to see the lists without using the GUI
• Improved message colors
• New helpful message reminder to quote your URLs
• Improved skin name resolving
• /sr setcustomname allows you to set a MiniMessage display name for any custom skin. They even allow RGB!
• Fix default permissions, /skin undo was before not given by default
• Downloaded version hash verification on bukkit. For people with bad internet like in China now builds should no longer be corrupted if the downloaded hash doesn't match.

Changes
0f6e0a5 Update dependency com.github.cryptomorin:XSeries to v11.2.0.1 ( #1729)
104f5e9 This commit marks release 15.4.0
53096ca Remove PlayerOrSkin enum by just using literals
ec0e4d0 Add debug info
63363ce Remove relocation of caffeine
5fce9d5 Add canonical instance class name to dump velocity
441170c Ensure packets are now coded incorrectly using type safety
700dac8 Fix reading and writing a few payloads
0b2d3bb Make message severe
65df533 Add warning if reloaded by PlugMan
84fc266 New Crowdin updates ( #1726)
7cefc2c Fix merged jar
eaf115a New Crowdin updates ( #1724)
f8b2833 Use dividers
01d1e4a Fix url edge cases in codebase
f7fc009 Add skin history and favourites commands and only show day, not specific daytimes
4d52cc1 Update dependency xyz.wagyourtail.jvmdowngrader:xyz.wagyourtail.jvmdowngrader.gradle.plugin to v0.9.1 ( #1725)
e4ef14c Downgrade jvmdowngrader again
aaff50d Improve UI design consistency
0196d4e Remove brigadier dependency
62a41f4 Disable native parsers
b9a19d7 Add annotations as annotation processor
f4299fd Fix locale
3f05b27 Add skin favourite cmd
b7aba91 Fix typo
f090233 Bump to snapshot
e67f58c Implement favourites through shift left click
c0a7fb9 Add favourite lore to GUI
816909e Add favourites menu to GUI
92fc2ac Fix next page button on empty page
bc20ecb Add favourites to storage
0102d41 Use verification header from GitHub releases
990588f Fix imports
83327bb Increase repeat duration
d797536 Fix tests by dropping caffeine
36b03de Notify users that urls need to be quoted
eecbe34 New translations locale.json (Chinese Simplified) ( #1723)
d7de59d New Crowdin updates ( #1721)
2736dd4 Use rgb format if available
80c57f4 Fix selector
df01523 Fix mysql typo
2e43936 Implement command to set custom skin display name
3299d02 Implement custom skin display names in storage
f8aa41d Support resolving recommendation skin name
96d3e35 New translations locale.json (Hungarian) ( #1720)
68e1bb7 Update config comments
100c719 Block commands if not in a server by default
87abac8 New Crowdin updates ( #1719)
10f5a9f Add new history gui and menu selector
c149947 Do not insert the same skin multiple times as history
812a5ab Grant access to undo by default
47a3600 Implement cooldown storage
28cca6b New translations locale.json (Russian) ( #1718)
3b40143 New Crowdin updates ( #1717)
fbeddef New Crowdin updates ( #1714)
3fae65d Fix actually downgrading files
0e70051 Finish up downgraded loading test support
84e50e1 Make easier to use relocated classes as base of tests
140be56 Fix jvmdowngrader ( #1716)
56efbfe Update dependency xyz.wagyourtail.jvmdowngrader:xyz.wagyourtail.jvmdowngrader.gradle.plugin to v0.9.1 ( #1715)
e00deb5 Implement better cooldown messages
253c84f Use seconds for now
378749b Remove excessive space
5866f8e Replace all String#format with String#formatted
50e83e0 New translations locale.json (Korean) ( #1713)