Code does not compile - does not support new version of gfortran

Current gfortran versions seems not compile eduplanet. Gives errors. Seems that version of gfortan is wrong.

Is there easy way to fix this?

My gcc version is

Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 12.3.0 (Ubuntu 12.3.0-1ubuntu1~23.04)

My Linux version is

lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 23.04 Release: 23.04 Codename: lunar