$ R CMD Rserve --no-save --RS-port 54321
R version 3.6.0 (2019-04-26) -- "Planting of a Tree"
[...]
Rserve started in daemon mode.
$ python -c "import pyRserve; import numpy; print(pyRserve.__version__); print(numpy.__version__); pyRserve.connect(port=54321).eval('1')"
0.9.1
1.16.3
[...]/pyRserve/rparser.py:316: DeprecationWarning: The binary mode of fromstring is deprecated, as it behaves surprisingly on unicode inputs. Use frombuffer instead
data = numpy.fromstring(raw, dtype=numpyMap[lexeme.rTypeCode])
I believe this should reproduce it: