The code refers to the watches in 44mm sizes, which is currently the larger of the two Watch sizes above the 40mm.
Image: iHelp BR
But given the excellent upgrade that the Series 4 was over the Series 3, it might be that these new models are simply new Series 4 editions if Apple feels it can’t fully update the Watch this year. The Series 4 was the first time the casing of the Watch had been redesigned, so even if a Series 5 were to launch it isn’t likely to be drastically different.
A titanium watch would reduce the bulk of the Watch as the material is quite lightweight. It’s used widely in the luxury watch market, so the move would see Apple further position itself as an affordable fashion alternative to popular high-end timepiece brands.
It’d also be a classic Apple move to encourage people to upgrade to a device not dissimilar from the last generation but that has visual differences.