Notice: Uninitialized string offset

Hi!
Sorry if I'm posting in the wrong place, I'm new here.

I'm using https://github.com/Frago9876543210/MCBE-Proxy, AKA MCPEProxy, it is outdated, so I suspect that I need to update some stuff. The problem is that I'm not really completely sure what to update. I've tried a bunch of stuff, and it only seems to crash the proxy. Here are some of the errors:

When looking:
Notice: Uninitialized string offset: 30 in C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\Binary.php on line 521

When moving, the proxy just pretty much crashes giving this error:
Fatal error: Uncaught TypeError: Return value of pocketmine\utils\Binary::readLFloat() must be of the type float, null returned in C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\Binary.php:306
Stack trace:
#0 C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\BinaryStream.php(179): pocketmine\utils\Binary::readLFloat('\x00\x01\x00')
#1 C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\pocketmine-mp\src\pocketmine\network\mcpe\protocol\MovePlayerPacket.php(66): pocketmine\utils\BinaryStream->getLFloat()
#2 C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\pocketmine-mp\src\pocketmine\network\mcpe\protocol\DataPacket.php(71): pocketmine\network\mcpe\protocol\MovePlayerPacket->decodePayload()
#3 C:\Users\impop\Desktop\MCPE P\src\proxy\hosts\Client.php(34): pocketmine\network\mcpe\protocol\DataPacket->decode()
#4 C:\Users\impop\Desktop\MCPE P\src\proxy\Proxy.php(103): proxy\hosts\Client->handleDataPacket(Object(pocketmine\network\mcpe\protocol\MovePlayerPacket))
#5 C:\Users\impop\Desktop\MCPE P\src\p in C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\Binary.php on line 306

When a message is sent:
Notice: Uninitialized string offset: 117 in C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\Binary.php on line 448

When jumping:
Notice: Uninitialized string offset: 30 in C:\Users\impop\Desktop\MCPE P\vendor\pocketmine\binaryutils\src\Binary.php on line 521

I installed everything from a composer file, and since it appears that the problems are coming from the vendor, I'll post what composer installed:

{
"name": "Frago9876543210/MCPE-Proxy",
"description": "Proxy for a Minecraft BE. It allows you to intercept packets and send packets.",
"type": "project",
"homepage": "https://github.com/Frago9876543210/MCPE-Proxy",
"license": "GPL-3.0",
"require": {
"php": ">=7.2.0RC3",
"ext-bcmath": "*",
"ext-curl": "*",
"ext-hash": "*",
"ext-json": "*",
"ext-mbstring": "*",
"ext-openssl": "*",
"ext-pcre": "*",
"ext-phar": "*",
"ext-pthreads": ">=3.1.7dev",
"ext-reflection": "*",
"ext-sockets": "*",
"ext-spl": "*",
"ext-yaml": ">=2.0.0",
"ext-zip": "*",
"ext-zlib": ">=1.2.11",
"pocketmine/pocketmine-mp": "dev-master",
"pocketmine/raklib": "dev-master",
"pocketmine/spl": "dev-master",
"pocketmine/binaryutils": "dev-master",
"pocketmine/nbt": "dev-master",
"pocketmine/math": "dev-master"
},
"autoload": {
"psr-4": {
"": [
"src"
]
}
},
"repositories": [
{
"type": "vcs",
"name": "pocketmine/pocketmine-mp",
"url": "https://github.com/pmmp/PocketMine-MP"
},
{
"type": "vcs",
"url": "https://github.com/pmmp/RakLib"
},
{
"type": "vcs",
"url": "https://github.com/pmmp/SPL"
},
{
"type": "vcs",
"url": "https://github.com/pmmp/BinaryUtils"
},
{
"type": "vcs",
"url": "https://github.com/pmmp/NBT"
},
{
"type": "vcs",
"url": "https://github.com/pmmp/Math"
}
]
}

I hope that is enough information to get somewhere.
Looking forward to a response!