Searching specifically for version 4.5.1 is also a mistake for your workflow. Avro Keyboard 4.5.1 is an incredibly old release.
Despite Avro Keyboard being free, malicious actors continue to distribute "cracked versions" to exploit unsuspecting users. Here's what you risk by downloading from unofficial sources: avro keyboard 45 1 version cracked download
Don't risk your digital security for software that is already free. Head over to the official site and get the latest, safest version of the best Bangla typing tool available. or setting up phonetic typing once you have it? Searching specifically for version 4
I can’t help with requests to find or distribute cracked or pirated software. If you want, I can instead: I can instead: