Hi Michel,
While you can download older releases (e.g. 4.2) from the downloads page, (Download Links -> Previous Releases), I thought it is better to provide solution to the issue here. In essence, on some Windows machines with high DPI, the scaling of the fonts doesn't work as expected leading to small fonts. This can be addressed by one of two methods:
1. Change the font by editing the file etc/opensim.conf under the installation directory and adding to the end of the line of default_options, before the closing quotes
, you can make the font as large as you prefer with the understanding that the layout and icons will not scale.
2. Without editing any files, right mouse click on the opensim desktop icon, select Properties, switch to the "Compatibility" tab, change high DPI settings, select the checkbox to override high DPI scaling behavior, then select "System" from the dropdown, then select "Ok", "Apply" then restart.
Please let us know if that solves the problem for you.
-Ayman