  The cyclic behaviour of (O-C) residuals of eclipse timings in the sdB+M
eclipsing binary NSVS 14256825 was previously attributed to one or two
Jovian-type circumbinary planets. We report 83 new eclipse timings that not
only fill in the gaps in those already published but also extend the time span
of the (O-C) diagram by three years. Based on the archival and our new data
spanning over more than 17 years we re-examined the up to date system (O-C).
The data revealed systematic, quasi-sinusoidal variation deviating from an
older linear ephemeris by about 100 s. It also exhibits a maximum in the (O-C)
near JD 2,456,400 that was previously unknown. We consider two most credible
explanations of the (O-C) variability: the light propagation time due to the
presence of an invisible companion in a distant circumbinary orbit, and
magnetic cycles reshaping one of the binary components, known as the Applegate
or Lanza-Rodono effect. We found that the latter mechanism is unlikely due to
the insufficient energy budget of the M-dwarf secondary. In the framework of
the third-body hypothesis, we obtained meaningful constraints on the Keplerian
parameters of a putative companion and its mass. Our best-fitting model
indicates that the observed quasi-periodic (O-C) variability can be explained
by the presence of a brown dwarf with the minimal mass of 15 Jupiter masses
rather than a planet, orbiting the binary in a moderately elliptical orbit (~
0.175) with the period of ~ 10 years. Our analysis rules out two planets model
proposed earlier.
