Describe the bug
A clear and concise description of what the bug is.

I am trying to compute thermochemical properties using the thermo submodule; however, the program is not able to read the hessian.out file from DFTB+.

My xtb command is as follows,

xtb thermo --sthr 100 --temp 298.15 geo_end_final.gen -dftb+ hessian.out

I am getting the following error,

[ERROR] Program stopped due to fatal error
-2- Could not read hessian from 'hessian.out'
-1- io_reader_readHessian: Could not find $hessian data group