Slack bot setup no longer possible?

[ErinFinnegan]

Describe the bug

I'm trying to follow this guide to connect my Discord to Slack: https://github.com/42wim/matterbridge/wiki/Slack-bot-setup#create-the-classic-slack-app

However, there is no longer the option to create classic Slack apps:

New creation of classic Slack apps has been discontinued
Creation of Slack classic apps has been discontinued since June 4, 2024. Learn how this may impact you and your team

To Reproduce
Steps to reproduce the behavior:

2. Use THIS LINK to create a "Slack App (Classic)". Choose any name for your app and select the desired workspace, and then submit. ⚠️ USE THE LINK AND DON'T CLICK THE "Create New App" BUTTON.

Click the link in step 2: https://api.slack.com/apps?new_classic_app=1

Apparently a redirect URL is required by Slack.. but I don't know if that's supposed to be my Slack workspace's URL or what...

... this doesn't seem to be required in the legacy app instructions.

[ReimarBauer]

Currently it looks like an existing old setup can become configured to bridge to an additional channel.
I do bridge libera.chat with slack.

I had to approve the app and added it to the apps. Invited the user to the channels I want to bridge.