I have been using Yamaha YRS-23 soprano recorder (German fingering) since primary school.
My school teacher used to borrow music period for other subjects, so I self-taught most of the recorder techniques (music theory comes from my piano lesson outside school).
I can manage C5 to A6 (excluding C#5 and D#5) consistently. Bb6 and B6 are not so stable, but I usually still can get them right after practicing the related music piece several times.
C7 sounds squeaky in > 90% of the time. I am unable to play C#7 and D7 without squeaking even if I adjust my fingering for one minute. Unfortunately, quite a lot of classical pieces do use these notes (since recorder has a pretty small pitch range) so I can't play them. Any tips?
By the way, the fingering chart came with the recorder is a bit different from Yamaha's online fingering chart (for Bb6, C#7 and D7). Yamaha's online fingering chart seems to be more consistent with other websites' chart (and easier), so I am following that instead.
A while ago I bought a Yamaha YRA-302B III alto recorder (Baroque fingering) as some pieces I want to play only fit into alto range. Quite expensive as it is a foreign product not imported in bulk (only one in store at that time). It definitely sounds more "real" than my soprano recorder. I can play the same B6 to D7 fingerings and they break less frequently. I wonder if this is due to "alto range" or "baroque design"?