diff --git a/api-openbis-python3-pybis/src/python/CHANGELOG.md b/api-openbis-python3-pybis/src/python/CHANGELOG.md
index 682a0df5180e38fe0b71bc30faf03f86d8228920..f9a9f9fe9823c9ba458fc415fa06b56a12392aa5 100644
--- a/api-openbis-python3-pybis/src/python/CHANGELOG.md
+++ b/api-openbis-python3-pybis/src/python/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Changes with pybis-1.35.11
+
+- Improvements to dataset upload performance
+
 ## Changes with pybis-1.35.10
 
 - Fixed issue with changing properties for linked datasets 
diff --git a/api-openbis-python3-pybis/src/python/pybis/__init__.py b/api-openbis-python3-pybis/src/python/pybis/__init__.py
index 5d5df0f11d731c9362661edc45000005ab7ad302..c2b117fa5198e446738104f6c00567f4f21ca0af 100644
--- a/api-openbis-python3-pybis/src/python/pybis/__init__.py
+++ b/api-openbis-python3-pybis/src/python/pybis/__init__.py
@@ -15,7 +15,7 @@
 name = "pybis"
 __author__ = "ID SIS • ETH Zürich"
 __email__ = "openbis-support@id.ethz.ch"
-__version__ = "1.35.10"
+__version__ = "1.35.11"
 
 from . import pybis
 from .pybis import DataSet
diff --git a/api-openbis-python3-pybis/src/python/pybis/dataset.py b/api-openbis-python3-pybis/src/python/pybis/dataset.py
index 9ba2f319b59b4f2e3776b74d40d077571bd6157f..7b29adfc32cd4c9f3b2e8cb2c680ce175f4a7016 100644
--- a/api-openbis-python3-pybis/src/python/pybis/dataset.py
+++ b/api-openbis-python3-pybis/src/python/pybis/dataset.py
@@ -1245,9 +1245,14 @@ class DataSetUploadQueue:
             file_size = os.path.getsize(filename)
 
             if self.multipart is True:
-                file = {filename: open(filename, "rb")}
-                resp = requests.post(upload_url, files=file, verify=verify_certificates)
-                resp.raise_for_status()
+                from requests_toolbelt.multipart.encoder import MultipartEncoder
+                with open(filename, "rb") as f:
+                    m = MultipartEncoder(
+                        fields={filename: (filename, f, 'application/octet-stream')})
+                    headers = {'Content-Type': m.content_type}
+                    r = requests.post(upload_url, data=m, headers=headers,
+                                      verify=verify_certificates)
+                    r.raise_for_status()
             else:
                 # upload the file to our DSS session workspace
                 with open(filename, "rb") as f:
diff --git a/api-openbis-python3-pybis/src/python/setup.cfg b/api-openbis-python3-pybis/src/python/setup.cfg
index 8c8e06e5b17f356187b80935a30471c5bbdab801..0cdcd3a74f79000a9bc01b08c97fa0134dde98a1 100644
--- a/api-openbis-python3-pybis/src/python/setup.cfg
+++ b/api-openbis-python3-pybis/src/python/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = PyBIS
-version = 1.35.10
+version = 1.35.11
 author = ID SIS • ETH Zürich
 author_email = openbis-support@id.ethz.ch
 license = Apache Software License Version 2.0
diff --git a/api-openbis-python3-pybis/src/python/setup.py b/api-openbis-python3-pybis/src/python/setup.py
index 6bf70e05b69b428fc82fc2954d76ba27e6ff2165..8d94cd3df9542c77a24724bba9eeff55acd43f1a 100644
--- a/api-openbis-python3-pybis/src/python/setup.py
+++ b/api-openbis-python3-pybis/src/python/setup.py
@@ -26,7 +26,7 @@ with open("README.md", "r", encoding="utf-8") as fh:
 
 setup(
     name="PyBIS",
-    version="1.35.10",
+    version="1.35.11",
     author="ID SIS • ETH Zürich",
     author_email="openbis-support@id.ethz.ch",
     description="openBIS connection and interaction, optimized for using with Jupyter",
diff --git a/api-openbis-python3-pybis/src/python/tests/jenkinstest/test.py b/api-openbis-python3-pybis/src/python/tests/jenkinstest/test.py
index 26e3904b7aa3a207205884a155caacd0c9eedbf6..f1700ac09ccd83dc62c0033822df4c78daa4073c 100644
--- a/api-openbis-python3-pybis/src/python/tests/jenkinstest/test.py
+++ b/api-openbis-python3-pybis/src/python/tests/jenkinstest/test.py
@@ -27,7 +27,7 @@ class TestCase(testcase.TestCase):
         self.openbisController = self.createOpenbisController()
         self.openbisController.allUp()
         # run tests
-        util.executeCommand(['pytest', '--junitxml=test_results_pybis.xml',
+        util.executeCommand(['pytest', '--verbose', '--junitxml=test_results_pybis.xml',
                              'api-openbis-python3-pybis/src/python/tests'])
 
 
diff --git a/app-openbis-command-line/src/python/CHANGELOG.md b/app-openbis-command-line/src/python/CHANGELOG.md
index d4bc519116d59a986d86dffb07734e6661ff845e..461d6c1c0acff0e347b2d373863655b5f80fe992 100644
--- a/app-openbis-command-line/src/python/CHANGELOG.md
+++ b/app-openbis-command-line/src/python/CHANGELOG.md
@@ -4,7 +4,7 @@
 * Added recursive search to object and data_set search commands
 * Updated documentation regarding authentication
 * Added dataset ids to sample search results
-* changed pybis dependency to version == 1.35.10
+* changed pybis dependency to version == 1.35.11
 
 # New in version 0.4.1
 
diff --git a/app-openbis-command-line/src/python/obis/__init__.py b/app-openbis-command-line/src/python/obis/__init__.py
index dd4ec142b180477405183dd6e20e9806e5aae0fb..bba01c84213abed1ed19e527218e764d35c95461 100644
--- a/app-openbis-command-line/src/python/obis/__init__.py
+++ b/app-openbis-command-line/src/python/obis/__init__.py
@@ -14,6 +14,6 @@
 #
 __author__ = "ID SIS • ETH Zürich"
 __email__ = "openbis-support@id.ethz.ch"
-__version__ = "0.4.2rc5"
+__version__ = "0.4.2rc6"
 
 from .dm import *
diff --git a/app-openbis-command-line/src/python/setup.py b/app-openbis-command-line/src/python/setup.py
index 29c14b57c26e007494206d4086176d30b924487e..267cea437ffead2b487d965101d0c14d3c6b91db 100644
--- a/app-openbis-command-line/src/python/setup.py
+++ b/app-openbis-command-line/src/python/setup.py
@@ -31,7 +31,7 @@ data_files = [
 
 setup(
     name="obis",
-    version="0.4.2rc5",
+    version="0.4.2rc6",
     description="Local data management with assistance from OpenBIS.",
     long_description=long_description,
     long_description_content_type="text/markdown",
@@ -42,7 +42,7 @@ setup(
     packages=["obis", "obis.dm", "obis.dm.commands", "obis.scripts"],
     data_files=data_files,
     package_data={"obis": ["dm/git-annex-attributes"]},
-    install_requires=["pyOpenSSL", "pytest", "pybis==1.35.10", "click"],
+    install_requires=["pyOpenSSL", "pytest", "pybis==1.35.11", "click"],
     entry_points={"console_scripts": ["obis=obis.scripts.cli:main"]},
     zip_safe=False,
     python_requires=">=3.3",
diff --git a/docs/software-developer-documentation/apis/python-v3-api.md b/docs/software-developer-documentation/apis/python-v3-api.md
index 9055bb1d98301aba1ddbac04271da61f78999c6b..22712262b1c173c42f46b8209e37db24cc7da58f 100644
--- a/docs/software-developer-documentation/apis/python-v3-api.md
+++ b/docs/software-developer-documentation/apis/python-v3-api.md
@@ -1540,4 +1540,4 @@ pt.save()
 Currently, the value of the `custom_widget` key can be set to either
 
 - `Spreadsheet` (for tabular, Excel-like data)
-- `Word Processor` (for rich text data)
\ No newline at end of file
+- `Word Processor` (for rich text data)