  Context. Cassiopeia A occupies an important place among supernova remnants
(SNRs) in low-frequency radio astronomy. The analysis of its continuum spectrum
from low frequency observations reveals the evolution of the SNR absorption
properties over time and suggests a method for probing unshocked ejecta and the
SNR interaction with the circumstellar medium (CSM). Aims. In this paper we
present low-frequency measurements of the integrated spectrum of Cassiopeia A
to find the typical values of free-free absorption parameters towards this SNR
in the middle of 2023. We also add new results to track its slowly evolving and
decreasing integrated flux density. Methods. We used the New Extension in
Nan\c{c}ay Upgrading LOFAR (NenuFAR) and the Ukrainian Radio Interferometer of
NASU (URAN-2, Poltava) for measuring the continuum spectrum of Cassiopeia A
within the frequency range of 8-66 MHz. The radio flux density of Cassiopeia A
has been obtained on June-July, 2023 with two sub-arrays for each radio
telescope, used as a two-element correlation interferometer. Results. We
measured magnitudes of emission measure, electron temperature and an average
number of charges of the ions for both internal and external absorbing ionized
gas towards Cassiopeia A from its integrated spectrum. Generally, their values
are comparable to those presented by Stanislavsky et al. (2023), but their
slight changes show the evolution of free-free absorption parameters in this
SNR. Based on high accuracy of the measurements, we have detected the SNR-CSM
interaction. Conclusions. The integrated flux-density spectrum of Cassiopeia A
obtained with the NenuFAR and URAN-2 interferometric observations opens up new
possibilities for continuous monitoring the ionized gas properties in and
around Cassiopeia A to observe theevolution of unshocked ejecta and the SNR-CSM
interaction in future studies.
