I believe the current version is 1.0.4, but how can I tell for sure? 1.0.5a is available and solves several problems.
Steps to Reproduce:
current version of alsa-lib is 1.0.6
You can check the version in include/sound/version.h. If you require a newer version you can always exclude ALSA from the kernel config and merge the "alsa-driver" package of any specific version in userspace.