Out of the box, the SMS subsystem will check an SMS provider supports the country code being sent to, however the initial implementation does not provide any UI mechanism for admins to control the order in which the providers are checked, so there is no easy way to manage the usage of multiple providers (for example having a primary and secondary provider as redundancy).

The scope of this issue is for site admins to be able to perform simple ordering via the table of SMS providers, so the first/top provider in the list will always be checked first for the ability to send an SMS, and working downwards.

Out of scope: Complex or detailed priority configurations are out of scope, such as per country code prioritisation. There is no indication this level of granularity is required at this stage, and these types of setups are likely achievable for those requiring them by combining the simple ordering with configurations on the provider side and the existing ability to create multiple provider instances (for example with some providers it would be possible to create multiple instances which support a subset of country codes, so more granular prioritisation could be achieved that way).