A list of the spec versions which the js-sdk is compatible with.
In practice, this means: when we connect to a server, it must declare support for one of the versions in this list.
Note that it does not necessarily mean that the js-sdk has good support for all the features in the listed spec
versions; only that we should be able to provide a base level of functionality with a server that offers support for
any of the listed versions.
A list of the spec versions which the js-sdk is compatible with.
In practice, this means: when we connect to a server, it must declare support for one of the versions in this list.
Note that it does not necessarily mean that the js-sdk has good support for all the features in the listed spec versions; only that we should be able to provide a base level of functionality with a server that offers support for any of the listed versions.