Reading of EEG file by mne shows - Channels contain different lowpass filters

Question

I have eeg files from BrainVision and would like to open it to dataset by mne (or any other pip lib) and I'm getting the error:

RuntimeWarning: Channels contain different lowpass filters. Highest (weakest) filter setting (131.00 Hz) will be stored.
  raw = mne.io.read_raw_brainvision('S01_base.vhdr', preload=True)

which is produced by code:

import mne

raw = mne.io.read_raw_brainvision('base.vhdr', preload=True)

events, event_ids = mne.events_from_annotations(raw)

I also tried to use for that task MathLab with EEGLab, but it is not installable in mathlab as I see :( I don't have any .edf file for example. So, how to get some dataset from .eeg file for example which will be like timestamp -> signal ?