There was a download of SIMUnlocker 2.0.0 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the program is iToolab Studio. We recommend checking the downloaded files with any free antivirus.
From the developer:
Quickly unlock carrier locked iPhone and use any SIM card from any carrier worldwide on it. Once an iPhones carrier lock has been removed you can take it anywhere in the world and use local SIM cards on it. This helps you in using any country or regions network and avoid roaming charges.
Quick unlock carrier locked iPhone without Chip.
Solve common SIM Card locked issues such as "SIM Card Not Valid", SIM Not Supported, SIM locked.
You may want to check out more software, such as iToolab SIMUnlocker, which might be related to SIMUnlocker.