Sony is one of the few manufacturers that actually announces smartphones at all three of the major trade shows (that's CES, MWC and IFA). At Mobile World Congress this year, the company debuted their Xperia X series, which is their flagship lineup and replaced the Xperia Z series. They announced the Xperia X, Xperia X Performance and Xperia XA at Mobile World Congress this past February, and the Xperia X Compact and Xperia XZ were announced at IFA in September. Now it appears that two more smartphones will be announced at Mobile World Congress next February, which will be the G3112 and G3121. It's unclear what smartphones these are, or what lineup they will be joining.
These two model numbers appeared in the European Economics Commission, which means they will be sold in Europe. Which is actually a pretty big market for Sony right now, especially since they are having trouble in the US. Since they have gone to the European Economics Commission, it's unlikely that they will debut at CES. It's also worth noting that Sony doesn't typically announce smartphones at CES – other than carrier-exclusives for the US – and they save their smartphone announcements for Mobile World Congress and IFA.
Everything here, about these two devices being announced at Mobile World Congress, should be taken with a grain of salt. Just like in the US when a smartphone visits the FCC, these two smartphones may not ever be released or announced. So we'll need to take it with a grain of salt and treat it as a leak, at least until we get closer to Mobile World Congress. Which is about four months away still. It's more than likely that Sony will debut new smartphones in Barcelona, but which smartphones are still up for debate. These could be new members of the Xperia X lineup, possibly an Xperia X2 and Xperia XA2, but we'll have to wait a bit longer to find out. Sony typically has a pretty big presence at Mobile World Congress in Barcelona, so it's not too surprising to see smartphones leaking out this early for the event. Hopefully the specs and names will appear pretty soon. So we can get a better picture of what Sony may be showing off.