[SOLVED] "Package does not exist" error because Conda cannot find recent package versions

"Package does not exist" error because Conda cannot find recent package versions

I have an existing Conda 23.1.0 environment managed using Mamba 1.5.1, which was created with the channels: conda-forge option. I want to install the latest version of the holidays package, which is 0.34.

However, mamba search holidays gives me

Loading channels: done
# Name                       Version           Build  Channel
holidays                       0.9.9            py_0  conda-forge
holidays                      0.9.10            py_0  conda-forge
...
holidays                        0.15    pyhd8ed1ab_0  conda-forge
holidays                        0.16    pyhd8ed1ab_0  conda-forge
holidays                        0.17    pyhd8ed1ab_0  conda-forge

If I try mamba install holidays=0.34 I get

Could not solve for environment specs
The following package could not be installed
└─ holidays 0.34**  does not exist (perhaps a typo or a missing channel).

How do I update the list of available packages so I can install the latest version?

[Edit] The first time I tried this, this error popped up about zstandard missing. When I installed zstandard, the error disappeared but it didn't solve the problem, hence this question

/opt/mambaforge/lib/python3.10/site-packages/conda_package_streaming/package_streaming.py:19: UserWarning: zstandard could not be imported. Running without .conda support.
  warnings.warn("zstandard could not be imported. Running without .conda support.")
/opt/mambaforge/lib/python3.10/site-packages/conda_package_handling/api.py:29: UserWarning: Install zstandard Python bindings for .conda support
  _warnings.warn("Install zstandard Python bindings for .conda support")

[Edit 2] As it turned out, this was the actual error that was hidden:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/opt/mambaforge/lib/python3.10/site-packages/zstandard/__init__.py", line 39, in <module>
    from .backend_c import *  # type: ignore
ImportError: zstd C API versions mismatch; Python bindings were not compiled/linked against expected zstd version (10505 returned by the lib, 10502 hardcoded in zstd headers, 10502 hardcoded in the cext)

Solution

Did you consider using the .conda file of your desired package : https://anaconda.org/conda-forge/holidays/files and install it from there ?

Note : I know nothing about Anaconda but i did some research and that's the best i can find to help you, hope it'll help you