Sagemath installation with apt package manager installs outdated version

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Hi all,

I'm attempting to install the latest version of sagemath, v9.4, with the recommended method of my linux distro's package manager. I'm running Ubuntu 20.04 through WSL2. I run the command

sudo apt install sagemath sagemath-jupyter sagemath-doc-en

and wait for installation to complete. After installation, I launch sage and observe the reported version

~ $ sage
┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 9.0, Release Date: 2020-01-01                     │
│ Using Python 3.8.10. Type "help()" for help.                       │
└────────────────────────────────────────────────────────────────────┘
sage:

and notice that it is version 9.0. This was after running

sudo apt update
sudo apt upgrade

so I believe my packages lists are up to date. Launching a Sage kernel in Jupyter reports the same version. This same behavior is observed on my other machine which runs the newest version of Linux Mint. Since pre-built binaries aren't available anymore, how can I get the latest version of Sage without needing to spend the time and effort installing from binaries?

Thank you for any insight you all might be able to provide :) I'm still very much an amateur with Linux and Sage and am still learning lots.