brew install old versions

cd to Homebrew's formula directory

cd $(brew --prefix)/Homebrew/Library/Taps/homebrew/homebrew-core/Formula

2) Find desired commit (version 63 for icu4c) to checkout

git log --follow icu4c.rb

3) Checkout to a new branch

git checkout -b icu4c-63 e7f0f10dc63b1dc1061d475f1a61d01b70ef2cb7

4) Reinstall the library with the new version

brew reinstall ./icu4c.rb

5) Switch to the reinstalled version

How to install PHP55 on Mac using brew

How to install PHP55 on Mac using brew

brew tap jdpedrie/php55
$ brew install php@5.5

brew tap exolnet/homebrew-deprecated

old version of openssl 

brew install rbenv/tap/openssl@1.0 [didnot work]

brew reinstall --build-from-source https://raw.githubusercontent.com/JParkinson1991/homebrew-deprecated/79d817a7ef794234d5276df0487a9d037b7b7bba/Formula/php@5.6.rb --with-openssl-1.1-patch 

https://getgrav.org/blog/macos-catalina-apache-multiple-php-versions