(solved) Game does not Start after patch 1.13.03 (Ubuntu Linux Mint 21.3)

[Maligneus]

I've been playing Gladius on Ubuntu Linux Mint 21.3 with an AMD GPU through Steam for several months without any issues.
After yesterday's patch the game client no longer starts. Please note that I have not changed any hardware, software or system configuration since before the patch.
Hitting the play button in Steam causes the following status messages: "Launching: synchronizing cloud", "Launching executable", "Checking", "Up to date".
And that is all. The actual game client never starts. There is no new entry in either the ErrorReporter.log or the Gladius.log.
I have already tried verifying game file integrity. The result reads:"All 13488 files successfully validated."

Solution:
Apparently the game was compiled with a newer version of libstdc++.so.6 using GLIBCXX_3.4.32.
I had to download and install gcc 4.9 from a new repository and upgrade the library manually.

Here are the steps I used:
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.9
sudo apt-get upgrade libstdc++6

So far the game seems to run fine.
In my opinion there really needs to by some kind of error message through Steam in case of a missing dependency.