Add more information about the ISO15118-20 implementation status

Signed-off-by: Fabian Hartung <fabian.hartung@chargebyte.com>

Author: FaHaGit

docs/source/troubleshooting.rst

@@ -92,7 +92,13 @@ Does EVerest on Charge SOM support ISO 15118-20 yet?
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The required module for ISO 15118-20 has been included in the image since the Charge SOM EVerest release 0.2.0.
-Please note that the implementation is still under development.
+Please note that the implementation is still under development and integrated into the image only for test purposes.
+
+EVerest integrates the `libiso15118 <https://github.com/EVerest/libiso15118>`_ library to provide support for ISO 15118-20.
+Here you can find more information about the current status of the ISO 15118-20 implementation.
+Please note, however, that the range of functions described in the linked `libiso15118` library documentation may not
+correspond to those already integrated in EVerest, as the library has not yet been fully integrated.
+Implementation gaps may exist, particularly in the case of BPT (bidirectional power transfer) functionality.
 
 
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