QIIME™ has been succeeded by QIIME 2™
QIIME 1 is no longer officially supported as our development and support efforts are now focused entirely on QIIME 2. You can learn more about this here.
If you're just getting started with QIIME, you should learn QIIME 2, not QIIME 1. QIIME 1 is outdated and QIIME 2 contains many improvements to analytic functionality, is easier to install, and is easier to use.
If you need to use QIIME 1, for example to reproduce old results, you can still access the original QIIME 1 website.