Why not install another copy of B4A somewhere other than the default, place the old libraries in its standard libraries folder and use it just for the one project? the two copies of the IDE will share the same settings from AppData\Roaming\Anywhere Softwate\Basic4android but that should not be a problem.
Also you could put the additional one in a sandbox, such as Sandboxie Plus to keep it separate from your main Windows installation
When I rename the OkHttpUtils2.b4xlib to OkHttpUtils2-2-96.b4xlib and then include the library OkHttpUtils2-2-96 (but not include the OkHttpUtils2 [which is 3.00])