This is old information for version before 2.3.0. Since that release the slider defaults to a range of 10m to 300m. It is the pilot's responsibility to act accordingly.
Yes. Map Pilot's altitude adjustment slider only allows you to select altitudes between 40m and 120m by default. These are sensible and safe numbers that were selected to keep people from crashing into things or easily breaking the law.
If you have a special need to fly higher or lower, we make it slightly inconvenient so people don't to it by accident.
To extend the altitude range beyond the defaults, you need to tap and hold the Altitude slider for 8 seconds (while remaining very still).
The range can currently be extended to 10 to 300 meters. We do not enable this by default since it is not something we recommend doing. 10 meter flights greatly increase the chances of hitting something and anything above 120 meters is not legal in the United States and a lot of other countries. If you wish to extend the range you may do so at your own risk.