7 > 11 would be a clean install and doesn't come for free.
But computer 18 months or older than the release of 11 are not suitable to run 11.
Windows 11 requirements;
https://docs.microsoft.com/en-us/windows/whats-new/windows-11-requirements
Specifically check this:
Processor: 1 gigahertz (GHz) or faster with two or more cores on a compatible 64-bit processor or system on a chip (SoC).
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Microsoft details what happens or won't happen if you install 11 on a device that does not meet minimum system requirements.
https://support.microsoft.com/en-us/windows/installing-windows-11-on-devices-that-don-t-meet-minimum-system-requirements-0b2dc4a2-5933-4ad4-9c09-ef0a331518f1
Remember: NO Security Updates.
Your device might malfunction due to these compatibility or other issues. Devices that do not meet these system requirements will no longer be guaranteed to receive updates, including but not limited to security updates.
This PC doesn't meet the minimum system requirements for running Windows 11 - these requirements help ensure a more reliable and higher quality experience. Installing Windows 11 on this PC is not recommended and may result in compatibility issues. If you proceed with installing Windows 11, your PC will no longer be supported and won't be entitled to receive updates. Damages to your PC due to lack of compatibility aren't covered under the manufacturer warranty.