The plugin still works fine but Wordfence shows a security warning for any plugin that use a Freemius SDK <= 2.5.9. SVG Flags was last updated in March 2022.

0.9.6, MAR 21, 2022
Updated Freemius SDK to v2.4.3.

Are there any plans to update the Freemius SDK package used in this plugin? Luckily the Freemius SDK uses the latest version if installed by any other plugin (https://freemius.com/blog/freemius-wordpress-sdk-security-vulnerability/) so there is no risk if you use other plugins that have been updated but this may not always be the case.