The 5.1 version of Lingr for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free software for Mac is Lingr.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The program lies within Communication Tools, more precisely Texting & Video calls.
From the developer:
Lingr lets you make group chats with ease, so remote workers can get things done faster. All chat logs are saved automatically unless you delete them. Better yet, each message has a permalink. On Lingr, private rooms are protected by a permission passphrase that is requested to everyone who wants to join. Each room has one or more owners. You can assign any number of moderators you like, or you can transfer ownership when you step down.
You may want to check out more software for Mac, such as ISL Pronto or Instant Messaging, which might be similar to Lingr.