Winbox 3.0 was a significant milestone in MikroTik's utility history. Released in late 2014 and 2015, it replaced the older Winbox 2.x branch and introduced a modernized interface that still defines the tool today. Key features introduced in this era include:
Improved ability to remember layout details between sessions and connect to multiple routers simultaneously. Why Download an Older Version? winbox old version 3.0 download
Administrators could finally group, filter, and search through large lists of saved routers. Winbox 3
The Winbox loader gained the ability to update itself automatically. Why Download an Older Version
Unless really-really needed, right now you will be better served by Winbox v. 3. x, at least until v. 4. x will exit the current " MikroTik community forum where can i get old WinBox versions? - MikroTik Forum
Added the ability to set a master password to encrypt the local router database for better security.
Most users are encouraged to use the latest stable version (currently in the 3.4x range or the newer v4 beta). However, specific use cases may lead you to search for the version 3.0 download: Why you should use Winbox - MikroTik Forum