Keep Older Version of Mail.app after Sonoma Update

[rickpoet]

Hi,

I'm wondering if it's possible to make a backup of the current version of Mail.app (Ventura) so when I update to Sonoma I can then replace Sonoma's mail.app with the Ventura version? (I rely on the MsgFiler plugin for filing messages into folders and Apple is removing plugin functionality from Sonoma's Mail.app)

Is this possible? Do I need to do anything more than copy the app or will I need to duplicate and restore files/folders from other parts of my Mac to make this work?

So in a nutshell – I want to update to Sonoma when it comes out...but somehow use Ventura's Mail.app?

Thanks for any advice.

R

 

[KoolAid-Drink]

Doubt you can, because of SIP. However, disabling SIP might help. I'll let more experienced users here pipe in, but it's possible Mail.app depends on certain system frameworks.

 

[rickpoet]

It's probably not a good sign that I don't know what SIP is or how to go about disabling it.

 

[haralds]

It's likely dependent on a bunch of Frameworks and APIs that have also changed.

 

[Malus120]

It's probably not a good sign that I don't know what SIP is or how to go about disabling it.

It is at the very least a sign that you will probably want to spend some time understanding what SIP (System Integrity Protection) does, and why you probably don't really want to disable it.
You can learn more here:

About System Integrity Protection on your Mac - Apple Support

System Integrity Protection is a security technology that helps protect your Mac from malicious software.

support.apple.com

What is SIP and when is it safe to turn it off?

System Integrity Protection can get in your way, and may be recommended to solve compatibility problems. It’s also changing again in Catalina.

eclecticlight.co

It's also a sign that you're probably going to want to find another solution for your email long term (preferably sooner rather than later), as relying on deprecated (in this case removed) software functionality is just going to cause you more issues going forward.

That said, in the meantime a relatively simple and safe solution would be to virtualize macOS Ventura on Sonoma and access the Ventura mail app (with the plugins you need) via that. There are lots of free applications that utilize Apple's lightweight virtualization framework that should be able to accomplish this task quite easily.

 

[winxmac]

Knowing that features/plugins you use may no longer work on the newer version, why upgrade?

I can upgrade officially to Monterey [MacBook Pro 2015] but decided to go back to Catalina... Monterey has some features only available for Apple Silicon devices and Catalina is the last intel only release that is why I decided to not go beyond Catalina even though I am using iOS 16.7 on iPhone 11 Pro Max...

 

[Fishrrman]

I'm thinking that with Sonoma, with Mail being one of Apple's primary applications, it's located within the "sealed system volume" and there is NO WAY that you will be able to use the older version after doing an upgrade. You (as the end user) can't even "see" the sealed system volume.

OP wrote:
"It's probably not a good sign that I don't know what SIP is or how to go about disabling it."

Then you had best not be fooling with anything that's "in there".
It could lead to some nasty problems.

If you upgrade to Sonoma, you're going to have to get used to the "new" Mail.app.
That's pretty much all there is to it...

 

[bogdanw]

While you can simply copy-paste the Mail app from Ventura into Sonoma /Applications, it doesn’t work. I tried.

"Termination Reason: Namespace DYLD, Code 4 Symbol missing
Symbol not found: _$s6MailUI0A11FeatureFlagO25zeroKeywordSearchMockDatayA2CmFWC
Referenced from: <A082FB4B-8662-3FF1-AB3D-9A2B9B0384AE> /Applications/Mail.app/Contents/MacOS/Mail
Expected in: <B668ABCE-793C-3863-802F-4918C2AE459D> /System/Library/PrivateFrameworks/MailUI.framework/Versions/A/MailUI"

 

[OldGreyGuy]

Wow! It disturbs me that I have been using mail for years (since Mountain Lion at least) and I did not know that the MsgFiler plugin existed.

This is the feature that I have used 3rd party mail clients for and putting up with their bugs, etc. Very sad.