The safest way to access the link is through the developer's official channels. Most indie creators host their work on:
An alternative for creators to share files with their community. bored kitty v021 link
If you played v0.20, back up your "saves" folder to avoid losing progress. The safest way to access the link is
Right-click the game icon and select "Run as Administrator" to ensure all features load correctly. bored kitty v021 link
Check the file size; v0.21 is typically larger than previous versions due to the added assets.
If the developer has made a public release, you can often find it on:
A popular platform for indie developers to host game files.