diff --git a/14085-extra-check.patch b/14085-extra-check.patch
new file mode 100644
index 0000000..bee7f2c
--- /dev/null
+++ b/14085-extra-check.patch
@@ -0,0 +1,48 @@
+From 42031876e16af041367c3066023994d4c970df57 Mon Sep 17 00:00:00 2001
+From: David Robertson <davidr@element.io>
+Date: Thu, 6 Oct 2022 15:46:11 +0100
+Subject: PR #14085 Unpin build-system requirements, but impose an upper-bound
+
+Fixes #14079, properly. Reverts #14080.
+
+A summary of the problem:
+
+Synapse defines an extra called url_preview with an underscore.
+Synapse looks up its own packaging metadata at runtime to check if the dependencies needed for url_preview are installed.
+Poetry-core 1.3.0 now normalises extra names when writing metadata, per PEP 685.
+This means the extra will be written to metadata as url-preview with a hyphen.
+So the lookup in point 2 will fail if Synapse was built/installed by poetry-core 1.3.0.
+
+--- a/pyproject.toml
++++ b/pyproject.toml
+@@ -219,7 +219,7 @@ oidc = ["authlib"]
+ # `systemd.journal.JournalHandler`, as is documented in
+ # `contrib/systemd/log_config.yaml`.
+ systemd = ["systemd-python"]
+-url_preview = ["lxml"]
++url-preview = ["lxml"]
+ sentry = ["sentry-sdk"]
+ opentracing = ["jaeger-client", "opentracing"]
+ jwt = ["authlib"]
+@@ -250,7 +250,7 @@ all = [
+     "pysaml2",
+     # oidc and jwt
+     "authlib",
+-    # url_preview
++    # url-preview
+     "lxml",
+     # sentry
+     "sentry-sdk",
+diff --git a/synapse/config/repository.py b/synapse/config/repository.py
+index 1033496bb43..e4759711ed9 100644
+--- a/synapse/config/repository.py
++++ b/synapse/config/repository.py
+@@ -205,7 +205,7 @@ def read_config(self, config: JsonDict, **kwargs: Any) -> None:
+         )
+         self.url_preview_enabled = config.get("url_preview_enabled", False)
+         if self.url_preview_enabled:
+-            check_requirements("url_preview")
++            check_requirements("url-preview")
+ 
+             proxy_env = getproxies_environment()
+             if "url_preview_ip_range_blacklist" not in config:
diff --git a/matrix-synapse.changes b/matrix-synapse.changes
index 3b59044..324ade9 100644
--- a/matrix-synapse.changes
+++ b/matrix-synapse.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Sat Oct 15 10:02:06 UTC 2022 - Ben Greiner <code@bnavigator.de>
+
+- Replace fragile workaround which is not specification compliant
+  with 14085-extra-check.patch -- gh#matrix-org/synapse#14085
+- Fix python site-packages fdupes
+
 -------------------------------------------------------------------
 Fri Oct 14 13:34:26 UTC 2022 - Marcus Rueckert <mrueckert@suse.de>
 
diff --git a/matrix-synapse.spec b/matrix-synapse.spec
index dc262aa..4c7ba09 100644
--- a/matrix-synapse.spec
+++ b/matrix-synapse.spec
@@ -176,12 +176,14 @@ Source99:       series
 Patch:          matrix-synapse-1.4.1-paths.patch
 Patch1:         bump-dependencies.patch
 Patch2:         https://patch-diff.githubusercontent.com/raw/matrix-org/synapse/pull/13952.patch
+# PATCH-FIX-UPSTREAM 14085-extra-check.patch https://github.com/matrix-org/synapse/pull/14085
+Patch3:         14085-extra-check.patch
 # https://github.com/matrix-org/synapse/pull/10719
 # disable by marking as source until we get a decision upstream
 Source100:      10719-Fix-instert-of-duplicate-key-into-event_json.patch
 BuildRequires:  %{use_python}-base >= 3.8
 BuildRequires:  %{use_python}-pip
-BuildRequires:  %{use_python}-poetry-core
+BuildRequires:  %{use_python}-poetry-core >= 1.0.0
 BuildRequires:  %{use_python}-setuptools
 BuildRequires:  %{use_python}-wheel
 BuildRequires:  cargo
@@ -194,7 +196,7 @@ BuildRequires:  unzip
 %{?systemd_ordering}
 %{sysusers_requires}
 %requires_peq   %{use_python}-base
-BuildRequires:  %{use_python}-setuptools-rust
+BuildRequires:  %{use_python}-setuptools-rust >= 1.3
 # NOTE: Keep this is in the same order as pyproject.toml.
 # some version locks based on poetry.lock
 BuildRequires:  %{use_python}-Jinja2 >= %{Jinja2_version}
@@ -333,14 +335,6 @@ cp %{S:48} README.SUSE
 install -d -m 0755 %{buildroot}%{_libexecdir}/%{pkgname}
 %pyproject_install
 
-# workaround for poetry >= 1.3.0 boo#1204312
-METADATA_FILE="%{buildroot}%{python3_sitearch}/%{eggname}-%{version}.dist-info/METADATA"
-if [ -e ${METADATA_FILE} ] ; then
-  perl -p -i.backup -e 's/(Provides-Extra: url-preview\n)/${1}Provides-Extra: url_preview\n/g' ${METADATA_FILE}
-  diff -urN ${METADATA_FILE}{.backup,} ||:
-  rm -f ${METADATA_FILE}.backup
-fi
-
 install -d -m 0755 %{buildroot}%{_bindir} %{buildroot}%{_libexecdir}/%{pkgname}/
 # move scripts to the old place.
 mv %{buildroot}%{_bindir}/* %{buildroot}%{_libexecdir}/%{pkgname}/
@@ -374,7 +368,7 @@ install -d -m 0750 %{buildroot}%{_rundir}/%{pkgname}
 install -d -m 0750 %{buildroot}%{_localstatedir}/lib/%{pkgname}
 install -d -m 0750 %{buildroot}%{_localstatedir}/log/%{pkgname}
 
-%fdupes %{buildroot}%{python3_sitelib}
+%fdupes %{buildroot}%{python3_sitearch}
 
 %pre -f %{name}.pre
 %service_add_pre %{pkgname}.service