In general you can downgrade a Xamarin product by running the old version of the installer package. For example, to downgrade from Xamarin.iOS 126.96.36.199 to Xamarin.iOS 188.8.131.52, run the
monotouch-184.108.40.206.pkg installer. Typically it is not necessary to uninstall the newer version of Xamarin before downgrading.
In some uncommon situations, downgrading without uninstalling the newer version might cause a problem. If the installer fails, or if your environment has difficulty loading or building projects, you might need to uninstall Xamarin before running the old installer package.
Compatibility issues can arise if you install one installer package without installing other corresponding packages. For example, if you develop in Xamarin Studio on Mac and downgrade from Xamarin.iOS 220.127.116.11 (Sep 19, 2014) to Xamarin.iOS 18.104.22.168 (Sep 8, 2014), we recommend you also downgrade Xamarin Studio from 5.4 (Sep 19, 2014) to 5.3 (Sep 9, 2014).
Links for the recent individual installer packages can be found on https://store.xamarin.com/account/my/subscription/downloads. If you do not yet have a Xamarin account, you can create one on https://www.xamarin.com/account/register.
Note about old versions
The downloads page only lists the last few Stable releases. If you wish to downgrade to an earlier version that is not shown, please send an email to email@example.com to request the download links you need.
Note about Beta and Alpha versions
The recommended way to update to Beta and Alpha versions is to change the updates channel. If you cannot use the IDE updater for some reason, you can send an email to firstname.lastname@example.org to request the download links.