diff --git a/evolution-data-server-3.40.0-ssl-trust-sha1-fallback.patch b/evolution-data-server-3.40.0-ssl-trust-sha1-fallback.patch
new file mode 100644
index 0000000..92d91b9
--- /dev/null
+++ b/evolution-data-server-3.40.0-ssl-trust-sha1-fallback.patch
@@ -0,0 +1,18 @@
+diff --git a/src/libedataserver/e-source-webdav.c b/src/libedataserver/e-source-webdav.c
+index 657d41da2..c4762895e 100644
+--- a/src/libedataserver/e-source-webdav.c
++++ b/src/libedataserver/e-source-webdav.c
+@@ -1520,7 +1520,12 @@ e_source_webdav_verify_ssl_trust (ESourceWebdav *extension,
+ 	if (decode_ssl_trust (extension, &response, &old_host, &old_hash)) {
+ 		gchar *hash;
+ 
+-		hash = g_compute_checksum_for_data (G_CHECKSUM_SHA256, bytes->data, bytes->len);
++		/* This is required for Flatpak, which can be built with eds before the 3.40, where
++		   had been changed to use SHA256. */
++		if (old_hash && strlen (old_hash) == g_checksum_type_get_length (G_CHECKSUM_SHA1) * 2)
++			hash = g_compute_checksum_for_data (G_CHECKSUM_SHA1, bytes->data, bytes->len);
++		else
++			hash = g_compute_checksum_for_data (G_CHECKSUM_SHA256, bytes->data, bytes->len);
+ 
+ 		if (response != E_TRUST_PROMPT_RESPONSE_UNKNOWN &&
+ 		    g_strcmp0 (old_host, host) == 0 &&
diff --git a/evolution-data-server.spec b/evolution-data-server.spec
index 436e846..78dadde 100644
--- a/evolution-data-server.spec
+++ b/evolution-data-server.spec
@@ -54,12 +54,14 @@
 
 Name: evolution-data-server
 Version: 3.40.0
-Release: 2%{?dist}
+Release: 3%{?dist}
 Summary: Backend data server for Evolution
 License: LGPLv2+
 URL: https://wiki.gnome.org/Apps/Evolution
 Source: http://download.gnome.org/sources/%{name}/3.40/%{name}-%{version}.tar.xz
 
+Patch01: evolution-data-server-3.40.0-ssl-trust-sha1-fallback.patch
+
 Provides: evolution-webcal = %{version}
 Obsoletes: evolution-webcal < 2.24.0
 
@@ -475,6 +477,9 @@ find $RPM_BUILD_ROOT -name '*.so.*' -exec chmod +x {} \;
 %{_datadir}/installed-tests
 
 %changelog
+* Mon Mar 29 2021 Milan Crha <mcrha@redhat.com> - 3.40.0-3
+- Resolves: #1943818 (ESourceWebDAV: Fallback to SHA1 on SSL trust verification if needed)
+
 * Fri Mar 26 2021 Kalev Lember <klember@redhat.com> - 3.40.0-2
 - Drop unnecessary requires on dconf