Feedback 2021.2.0a19 Mono Upgrade

The latest patch notes show a mono upgrade:

Code (text):

1. Mono: Upgraded to a recent version of Mono (~6.12) which brings many bug fixes from upstream Mono project.

May we know the previous version so we can look up what changes happened to Mono since the previous version? It would be helpful to have this "from X to Y" information in all patch notes.

 

If the output of those is correct, we went from 5.11.0 to 6.13.0

C:\Program Files\Unity\Hub\Editor\2021.2.0a17\Editor\Data\MonoBleedingEdge\bin>mono --version
Mono JIT compiler version 5.11.0 (Visual Studio built mono)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: normal
SIGSEGV: normal
Notification: Thread + polling
Architecture: x86
Disabled: none
Misc: softdebug
Interpreter: yes
LLVM: supported, not enabled.
GC: sgen (concurrent by default)


C:\Program Files\Unity\Hub\Editor\2021.2.0a19\Editor\Data\MonoBleedingEdge\bin>mono --version
Mono JIT compiler version 6.13.0 (Visual Studio built mono)
Copyright (C) Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: __thread
SIGSEGV: normal
Notification: Thread + polling
Architecture: x86
Disabled: none
Misc: softdebug
Interpreter: yes
Suspend: preemptive
GC: sgen (concurrent by default)

 

What are the best things the upgrade brings to the table?

 

.Net Standard 2.1, full C# 9 Support (not active yet) and so far i know Mono not longer convert floats to double..

 

That's the compiler version, not the mono version. 6.13 is not even released for Mono. The latest is 6.12

 

"Mono JIT compiler" So its the runtime. As C# Compiler Unity use Roslyn. And since 2019.3 Unity contain only one Mono version.

 

Unity has always used a bifurcated version of mono, the last information I found was in this topic:

"We are currently using a branch based off Mono 4.8."
https://forum.unity.com/threads/future-plans-for-the-mono-runtime-upgrade.464327/#post-3018676

Mono: 4.8.0.495 - Initial stable release (22 Feb 2017)
https://www.mono-project.com/docs/about-mono/releases/4.8.0

This may not be the most recent version they were using, but in order to be recorded in the changelog, there has definitely been a big change to Unity's internal API.

Anyway, this indicates cool things coming
(NET 5 or 6 support)

 

https://github.com/Unity-Technologies/mono Unity mono fork.