Date: 2018-08-29
Superceded by 7. Require latest stable PHP version
Deciding which minimum PHP version to require is quite important because it might restrict people from using the library, at the same time supporting many versions increases the cost to maintain the library.
For the first releases of this library we'll be requiring PHP 7.2+ (64-bit build only).
The main motivation for only allowing it to be installed in 64-bit systems is that Kafka's protocol uses signed longs (64-bit integers) for some fields, which can't be achieve in 32-bit systems.
I believe that libraries' maintainers also have the role to help the evolution of the PHP ecosystem, which makes me want to require a more up-to-date version of the language.
This decision shouldn't be a general problem, considering that Kafka is a relatively new tool in our stack and it doesn't make much sense to me to want to use it with an old version of PHP.