Latest version for PowerBook 100

Hi,

System 7.5.5.

If you need technical information about older Macs, there are several ways to find it.

One method is to go to Apple's main support page Official Apple Support. Under Resources, you will find a link to Tech Specs (Apple - Support - Technical Specifications). In this case, choose Mac notebooks. Now, repeatedly, click on the Load more results button until you locate the computer in question: Macintosh PowerBook 100: Technical Specifications.

Another way would be to go to everymac.com. Under the specifications for each model, you will find the original and other supported operating systems.