ImportError: cannot import name 'Markup' from 'flask'

[tobiasstrauss]

after running the WebServer by python thunderbird/webserver.py
ImportError: cannot import name 'Markup' from 'flask'

Here are the dependencies:

APScheduler==3.10.4
blinker==1.7.0
Bootstrap-Flask==2.3.2
certifi==2023.11.17
charset-normalizer==3.3.2
click==8.1.7
contourpy==1.2.0
cycler==0.12.1
dicttoxml2==2.1.0
Flask==3.0.0
Flask-Dropzone==1.6.0
Flask-HTTPAuth==4.8.0
Flask-Login==0.6.3
Flask-SQLAlchemy==3.1.1
Flask-WTF==1.2.1
fonttools==4.45.0
ftfy==6.1.3
greenlet==3.0.1
idna==3.4
isodate==0.6.1
itsdangerous==2.1.2
Jinja2==3.1.2
jsonpickle==1.5.2
kiwisolver==1.4.5
MarkupSafe==2.1.3
matplotlib==3.7.4
numpy==1.26.2
packaging==23.2
pandas==2.1.3
Pillow==10.1.0
pydevd==2.10.0
PyDispatcher==2.0.7
pyFlaskBootstrap4==0.6.1
Pygments==2.17.2
pylatexenc==2.10
pyLodStorage==0.4.14
pyparsing==3.1.1
python-dateutil==2.8.2
pyThunderbird @ file:///home/tobias/tmp/pyThunderbird/pyThunderbird
pytz==2023.3.post1
PyYAML==6.0.1
rdflib==7.0.0
requests==2.31.0
six==1.16.0
SPARQLWrapper==1.8.5
SQLAlchemy==2.0.23
SQLAlchemy-Utils==0.41.1
tabulate==0.9.0
typing_extensions==4.8.0
tzdata==2023.3
tzlocal==5.2
urllib3==2.1.0
wcwidth==0.2.12
Werkzeug==3.0.1
WTForms==3.1.1

[WolfgangFahl]

The upstream Flask library is incompatible by now. We'll have to implement #16 as a clean way out of this.