GEDmatch has two ways of getting the raw data from 23andme. If one of them doesn't work, the other one might. There have been no changes to the data format that GedMatch can't handle.
One way is a new one: "fast & easy". I have not used this, so cannot give detail. In short, though, from GedMatch you are routed to 23andMe's site to give authorization to logon to the person's 23andme account, and GedMatch then accesses the data. In the past year, 23andMe has been transitioning to a new user interface, but I don't know if that affects the GedMatch "fast & easy" method.
The other way is labeled "Old method". It should work without regard to the 23andMe user interface. It involves first going to 23andme and downloading the person's raw data, which is delivered as a "zip" file. One then goes to GedMatch and uses the "Old method" to upload the same "zip" file.
"Having trouble uploading" is very non-specific, so it's not easy to troubleshoot. Can the person access their results on 23andMe? If not, it would seem that the laboratory results are not yet available (so GedMatch couldn't use them).