WHY the Aria would be using a B connection is beyond me. B has not been a main standard for.. has to be 8+ years?
Unfortunately, i dont think there really IS a solution.. bar setting up a cheap wireless access point, which has B capabilities.. JUST for the scale.
Well, when you consider that last years Nest products are N 2.4 only, I would suspect that a lot of these IoT companies are building their products with bottom of the barrel networking parts in them.
The new Aria 2 scale markets specifically that it has a wider range of network connections available, so suspect that they are in an indirect way saying, buy only the 2, not any original ones kicking around.
By the way, B and A was 1999, G was 2003, N was 2009 and AC was 2013. In an article by Cisco, they were advising in 2014 to phase out b devices. So, don't know the first year of distribution of the aria, but that is only 2014 that Cisco recommended phasing it out given that G and N had been around since 2003 and 2009, and AC was just out then.
So slipping in hardware that only supports one of the standards, like B for the Aria and N for the Nest E keeps their production costs down, but unfortunately, a lot of people will be stuck without wireless connection on new routers or gateways. Nest for example lists a whole range of routers that are not compatible with the various devices on their site.
Yes, you could for about 39.00 or a bit lower get an access point (not a repeater setup), but that means you need Ethernet to connect it too so you can get b/g/n/ac connections. My access point fortunately has that full option. Obsolescence hits all of our stuff sooner or later unfortunately.
I recommend that when one is looking at new routers or access points, or Ignite and newer gateways from any company, that you check the specs on both the router and the device to see if they will be compatible. Glad that @iponting got a new one - I have found that Fitbit has great support and helps people through these struggles with very clear cut recommendations. I rate them as having the best tech support and customer support of any company I have dealt with.