ERROR: Package 'xarray' requires a different Python: 3.6.15 not in '>=3.7'

[emoen]

When running: conda env create python=3.6 -f C:\prosjekt\ML_Finance_Codes\environment.yml
or conda env create -f C:\prosjekt\ML_Finance_Codes\environment.yml

with anaconda 3, python 3.9.7 -64 bits, I get error installing xarray:

Requirement already satisfied, skipping upgrade: cached-property; python_version < "3.8" in c:\users\endre\anaconda3\envs\mlfenv\lib\site-packages (from h5py>=2.7.0->pymc3==3.8->-r C:\prosjekt\ML_Finance_Codes\condaenv.s7kg5d46.requirements.txt (line 2)) (1.5.2)
Requirement already satisfied, skipping upgrade: matplotlib>=3.0 in c:\users\endre\anaconda3\envs\mlfenv\lib\site-packages (from arviz>=0.4.1->pymc3==3.8->-r C:\prosjekt\ML_Finance_Codes\condaenv.s7kg5d46.requirements.txt (line 2)) (3.1.3)
Requirement already satisfied, skipping upgrade: xarray>=0.11 in c:\users\endre\anaconda3\envs\mlfenv\lib\site-packages (from arviz>=0.4.1->pymc3==3.8->-r C:\prosjekt\ML_Finance_Codes\condaenv.s7kg5d46.requirements.txt (line 2)) (0.18.2)

Pip subprocess error:
ERROR: Package 'xarray' requires a different Python: 3.6.15 not in '>=3.7'

failed

CondaEnvException: Pip failed

[emoen]

no error when moving - pymc3==3.8 from pip to top of dependencies list