diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index cf5215c014f3dea2a872e706ee033404b8f4a39c..9f74e6dca4c9dc3dca4175f28c3d106d2e7cfc1a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,26 +2,39 @@ stages:
   - build
   - test
 
+variables:
+  FEATURES: ""
+
 rust-latest-build:
   stage: build
   image: rust:latest
   script:
-    - cargo build --verbose
+    - cargo build --verbose --no-default-features --features=$FEATURES
 
 rust-nightly-build:
   stage: build
   image: rustlang/rust:nightly
   script:
-    - cargo build --verbose
+    - cargo build --verbose --no-default-features --features=$FEATURES
 
 rust-latest-test:
   stage: test
   image: rust:latest
   script:
-    - cargo test --verbose
+    - cargo test --verbose --no-default-features --features=$FEATURES
 
 rust-nightly-test:
   stage: test
   image: rustlang/rust:nightly
   script:
-    - cargo test --verbose
+    - cargo test --verbose --no-default-features --features=$FEATURES
+
+"rust-latest-test with features=disable-validation":
+  extends: rust-latest-test
+  variables:
+    FEATURES: "disable-validation"
+
+"rust-nightly-test with features=disable-validation":
+  extends: rust-nightly-test
+  variables:
+    FEATURES: "disable-validation"
diff --git a/Cargo.toml b/Cargo.toml
index 2d3122cb9084fd17e1434003c591f8e2036d1454..0e3b9a36dbde483ea64a3f00074fcfd2d1a29199 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,3 +28,5 @@ try_from = "0.3.2"
 [features]
 # Build xmpp-parsers to make components instead of clients.
 component = []
+# Disable validation of unknown attributes.
+disable-validation = []
diff --git a/src/attention.rs b/src/attention.rs
index be33bb3b6f07d002163bfa2ee46d4f3a7bc6b6c3..bd4c7a15e431cc8f5548cd837b96f97abbc59968 100644
--- a/src/attention.rs
+++ b/src/attention.rs
@@ -18,6 +18,7 @@ impl MessagePayload for Attention {}
 #[cfg(test)]
 mod tests {
     use super::*;
+    #[cfg(not(feature = "disable-validation"))]
     use crate::error::Error;
     use minidom::Element;
     use try_from::TryFrom;
@@ -33,6 +34,7 @@ mod tests {
         Attention::try_from(elem).unwrap();
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_child() {
         let elem: Element = "<attention xmlns='urn:xmpp:attention:0'><coucou/></attention>"
@@ -46,6 +48,7 @@ mod tests {
         assert_eq!(message, "Unknown child in attention element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<attention xmlns='urn:xmpp:attention:0' coucou=''/>"
diff --git a/src/bind.rs b/src/bind.rs
index fe9472b2cc3c2192c959cd7c076dc87d9adc2786..9d3a894f8950c2aee20cda960de6b17acc6a4bac 100644
--- a/src/bind.rs
+++ b/src/bind.rs
@@ -112,6 +112,7 @@ mod tests {
         assert_eq!(bind, Bind::None);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_resource() {
         let elem: Element = "<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><resource attr='coucou'>resource</resource></bind>"
diff --git a/src/blocking.rs b/src/blocking.rs
index d34fee3d97a1935c5d825e7bfc836408e74885a2..53417f7f749ccebc425fceeee2da39d63b03f337 100644
--- a/src/blocking.rs
+++ b/src/blocking.rs
@@ -155,14 +155,6 @@ mod tests {
             },
         ];
 
-        let request_elem = elem.clone();
-        let error = BlocklistRequest::try_from(request_elem).unwrap_err();
-        let message = match error {
-            Error::ParseError(string) => string,
-            _ => panic!(),
-        };
-        assert_eq!(message, "Unknown child in blocklist element.");
-
         let result_elem = elem.clone();
         let result = BlocklistResult::try_from(result_elem).unwrap();
         assert_eq!(result.items, two_items);
@@ -176,6 +168,7 @@ mod tests {
         assert_eq!(unblock.items, two_items);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid() {
         let elem: Element = "<blocklist xmlns='urn:xmpp:blocking' coucou=''/>"
@@ -217,4 +210,16 @@ mod tests {
         };
         assert_eq!(message, "Unknown attribute in unblock element.");
     }
+
+    #[cfg(not(feature = "disable-validation"))]
+    #[test]
+    fn test_non_empty_blocklist_request() {
+        let elem: Element = "<blocklist xmlns='urn:xmpp:blocking'><item jid='coucou@coucou'/><item jid='domain'/></blocklist>".parse().unwrap();
+        let error = BlocklistRequest::try_from(elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "Unknown child in blocklist element.");
+    }
 }
diff --git a/src/caps.rs b/src/caps.rs
index 72b04263f14bfd58a51276de57be39026c63d21e..74042be31a368be7a0d5b756a7393ec0ad77a09c 100644
--- a/src/caps.rs
+++ b/src/caps.rs
@@ -233,6 +233,7 @@ mod tests {
         );
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_child() {
         let elem: Element = "<c xmlns='http://jabber.org/protocol/caps'><hash xmlns='urn:xmpp:hashes:2' algo='sha-256'>K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4=</hash></c>".parse().unwrap();
diff --git a/src/chatstates.rs b/src/chatstates.rs
index 75d64d91b1549651793e2fd2c2775f811743f64a..4eb173f11b796d1ef554f7f766638de486efef6f 100644
--- a/src/chatstates.rs
+++ b/src/chatstates.rs
@@ -63,6 +63,7 @@ mod tests {
         assert_eq!(message, "This is not a chatstate element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_child() {
         let elem: Element = "<gone xmlns='http://jabber.org/protocol/chatstates'><coucou/></gone>"
@@ -76,6 +77,7 @@ mod tests {
         assert_eq!(message, "Unknown child in chatstate element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<inactive xmlns='http://jabber.org/protocol/chatstates' coucou=''/>"
diff --git a/src/jingle_ft.rs b/src/jingle_ft.rs
index 381eb21fa288b1c37ac00ef139d4f033750b454c..32dd41f6aeb7233bc5a236796ea7bfa6fa80418f 100644
--- a/src/jingle_ft.rs
+++ b/src/jingle_ft.rs
@@ -510,14 +510,6 @@ mod tests {
         };
         assert_eq!(message, "Unknown child in received element.");
 
-        let elem: Element = "<received xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='initiator' coucou=''/>".parse().unwrap();
-        let error = Received::try_from(elem).unwrap_err();
-        let message = match error {
-            Error::ParseError(string) => string,
-            _ => panic!(),
-        };
-        assert_eq!(message, "Unknown attribute in received element.");
-
         let elem: Element =
             "<received xmlns='urn:xmpp:jingle:apps:file-transfer:5' creator='initiator'/>"
                 .parse()
@@ -538,6 +530,18 @@ mod tests {
         assert_eq!(message, "Unknown value for 'creator' attribute.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
+    #[test]
+    fn test_invalid_received() {
+        let elem: Element = "<received xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='initiator' coucou=''/>".parse().unwrap();
+        let error = Received::try_from(elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "Unknown attribute in received element.");
+    }
+
     #[test]
     fn test_checksum() {
         let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='initiator'><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
@@ -575,29 +579,33 @@ mod tests {
         };
         assert_eq!(message, "This is not a file element.");
 
-        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='initiator' coucou=''><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
+        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' creator='initiator'><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
         let error = Checksum::try_from(elem).unwrap_err();
         let message = match error {
             Error::ParseError(string) => string,
             _ => panic!(),
         };
-        assert_eq!(message, "Unknown attribute in checksum element.");
+        assert_eq!(message, "Required attribute 'name' missing.");
 
-        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' creator='initiator'><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
+        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='coucou'><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
         let error = Checksum::try_from(elem).unwrap_err();
         let message = match error {
             Error::ParseError(string) => string,
             _ => panic!(),
         };
-        assert_eq!(message, "Required attribute 'name' missing.");
+        assert_eq!(message, "Unknown value for 'creator' attribute.");
+    }
 
-        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='coucou'><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
+    #[cfg(not(feature = "disable-validation"))]
+    #[test]
+    fn test_invalid_checksum() {
+        let elem: Element = "<checksum xmlns='urn:xmpp:jingle:apps:file-transfer:5' name='coucou' creator='initiator' coucou=''><file><hash xmlns='urn:xmpp:hashes:2' algo='sha-1'>w0mcJylzCn+AfvuGdqkty2+KP48=</hash></file></checksum>".parse().unwrap();
         let error = Checksum::try_from(elem).unwrap_err();
         let message = match error {
             Error::ParseError(string) => string,
             _ => panic!(),
         };
-        assert_eq!(message, "Unknown value for 'creator' attribute.");
+        assert_eq!(message, "Unknown attribute in checksum element.");
     }
 
     #[test]
@@ -627,7 +635,11 @@ mod tests {
         assert_eq!(range2.offset, 2048);
         assert_eq!(range2.length, Some(1024));
         assert_eq!(range2.hashes, hashes);
+    }
 
+    #[cfg(not(feature = "disable-validation"))]
+    #[test]
+    fn test_invalid_range() {
         let elem: Element = "<range xmlns='urn:xmpp:jingle:apps:file-transfer:5' coucou=''/>"
             .parse()
             .unwrap();
diff --git a/src/macros.rs b/src/macros.rs
index 62c59736dc5a52435d988e88b30597f22a3f5097..aa89a45cbe2b6c429ef7c6300c75cc8fcc49621c 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -248,6 +248,7 @@ macro_rules! check_ns_only {
 
 macro_rules! check_no_children {
     ($elem:ident, $name:tt) => {
+        #[cfg(not(feature = "disable-validation"))]
         for _ in $elem.children() {
             return Err(crate::error::Error::ParseError(concat!(
                 "Unknown child in ",
@@ -260,6 +261,7 @@ macro_rules! check_no_children {
 
 macro_rules! check_no_attributes {
     ($elem:ident, $name:tt) => {
+        #[cfg(not(feature = "disable-validation"))]
         for _ in $elem.attrs() {
             return Err(crate::error::Error::ParseError(concat!(
                 "Unknown attribute in ",
@@ -272,6 +274,7 @@ macro_rules! check_no_attributes {
 
 macro_rules! check_no_unknown_attributes {
     ($elem:ident, $name:tt, [$($attr:tt),*]) => (
+        #[cfg(not(feature = "disable-validation"))]
         for (_attr, _) in $elem.attrs() {
             $(
                 if _attr == $attr {
diff --git a/src/message_correct.rs b/src/message_correct.rs
index 9e7a08f726c1e789b2794949a3888ec4d8524eb8..3bba10e7a187abf3cb1fcdb2e116a9b014fda2f8 100644
--- a/src/message_correct.rs
+++ b/src/message_correct.rs
@@ -45,6 +45,7 @@ mod tests {
         Replace::try_from(elem).unwrap();
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<replace xmlns='urn:xmpp:message-correct:0' coucou=''/>"
diff --git a/src/muc/muc.rs b/src/muc/muc.rs
index 32df468d7e46f8548656f6a9503daef514dc610f..fc596fa9c95adfe4f759cefead11bbabca89974e 100644
--- a/src/muc/muc.rs
+++ b/src/muc/muc.rs
@@ -142,6 +142,7 @@ mod tests {
         assert_eq!(elem, elem2);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_muc_invalid_attribute() {
         let elem: Element = "<x xmlns='http://jabber.org/protocol/muc' coucou=''/>"
diff --git a/src/muc/user.rs b/src/muc/user.rs
index 2c1a6926a98b9099f207268bcb683ec9127070a1..56c111e8ef18b7cd8a6be65a3544bdff4bb17efb 100644
--- a/src/muc/user.rs
+++ b/src/muc/user.rs
@@ -303,6 +303,7 @@ mod tests {
         assert!(elem.compare_to(&elem2));
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "
@@ -343,6 +344,7 @@ mod tests {
         assert_eq!(message, "Required attribute 'code' missing.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_status_invalid_child() {
         let elem: Element = "
@@ -513,6 +515,7 @@ mod tests {
         assert_eq!(reason.0, "Reason".to_owned());
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_reason_invalid_attribute() {
         let elem: Element = "
@@ -528,6 +531,7 @@ mod tests {
         assert_eq!(message, "Unknown attribute in reason element.".to_owned());
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_reason_invalid() {
         let elem: Element = "
@@ -545,6 +549,7 @@ mod tests {
         assert_eq!(message, "Unknown child in reason element.".to_owned());
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_item_invalid_attr() {
         let elem: Element = "
diff --git a/src/nick.rs b/src/nick.rs
index edf8dcacce17b23e54ac39fcbea32b87aad8d5a2..03f544aaa9455e9d9b8894972098676b9f898df2 100644
--- a/src/nick.rs
+++ b/src/nick.rs
@@ -14,6 +14,7 @@ generate_elem_id!(
 #[cfg(test)]
 mod tests {
     use super::*;
+    #[cfg(not(feature = "disable-validation"))]
     use crate::error::Error;
     use minidom::Element;
     use try_from::TryFrom;
@@ -48,6 +49,7 @@ mod tests {
         assert_eq!(elem1, elem2);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid() {
         let elem: Element = "<nick xmlns='http://jabber.org/protocol/nick'><coucou/></nick>"
@@ -61,6 +63,7 @@ mod tests {
         assert_eq!(message, "Unknown child in nick element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<nick xmlns='http://jabber.org/protocol/nick' coucou=''/>"
diff --git a/src/ping.rs b/src/ping.rs
index 4cb25f649c453db84f9879f5871c743df187898f..018531205c3d16f9b6b681251fe12091b1e091ab 100644
--- a/src/ping.rs
+++ b/src/ping.rs
@@ -20,6 +20,7 @@ impl IqGetPayload for Ping {}
 #[cfg(test)]
 mod tests {
     use super::*;
+    #[cfg(not(feature = "disable-validation"))]
     use crate::error::Error;
     use minidom::Element;
     use try_from::TryFrom;
@@ -42,6 +43,7 @@ mod tests {
         assert_eq!(elem1, elem2);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid() {
         let elem: Element = "<ping xmlns='urn:xmpp:ping'><coucou/></ping>"
@@ -55,6 +57,7 @@ mod tests {
         assert_eq!(message, "Unknown child in ping element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<ping xmlns='urn:xmpp:ping' coucou=''/>".parse().unwrap();
diff --git a/src/presence.rs b/src/presence.rs
index 1f9846c2b7dc493b5f37d6c135327ebfcd125a68..7e3e8aa8f78a6afb68bfd7430467580f96a7e527 100644
--- a/src/presence.rs
+++ b/src/presence.rs
@@ -570,6 +570,7 @@ mod tests {
         assert!(payload.is("test", "invalid"));
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_status_child() {
         #[cfg(not(feature = "component"))]
@@ -589,6 +590,7 @@ mod tests {
         assert_eq!(message, "Unknown child in status element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         #[cfg(not(feature = "component"))]
diff --git a/src/pubsub/event.rs b/src/pubsub/event.rs
index fac8e2fe26b822297abf1438cfe6ae4332bd065d..0cef2c397c453bf00b9bddb5e08d43158a2a9e60 100644
--- a/src/pubsub/event.rs
+++ b/src/pubsub/event.rs
@@ -420,6 +420,7 @@ mod tests {
         assert_eq!(message, "Unknown child in event element.");
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid_attribute() {
         let elem: Element = "<event xmlns='http://jabber.org/protocol/pubsub#event' coucou=''/>"
diff --git a/src/roster.rs b/src/roster.rs
index 40cc7a25dc7f8a7f935306df4507e3cff8d4862e..c13b0f59ad1eed7cc791c8ac512a56b721056ebd 100644
--- a/src/roster.rs
+++ b/src/roster.rs
@@ -245,6 +245,7 @@ mod tests {
         assert_eq!(roster.items[0].subscription, Subscription::Remove);
     }
 
+    #[cfg(not(feature = "disable-validation"))]
     #[test]
     fn test_invalid() {
         let elem: Element = "<query xmlns='jabber:iq:roster'><coucou/></query>"
diff --git a/src/sasl.rs b/src/sasl.rs
index 05dd250aba849569c445349720e024dee0e0179a..db9b17e6fd3a90f071898c15cad65054fdd0dde3 100644
--- a/src/sasl.rs
+++ b/src/sasl.rs
@@ -288,4 +288,23 @@ mod tests {
             String::from("Call 212-555-1212 for assistance.")
         );
     }
+
+    /// Some servers apparently use a non-namespaced 'lang' attribute, which is invalid as not part
+    /// of the schema.  This tests whether we can parse it when disabling validation.
+    #[cfg(feature = "disable-validation")]
+    #[test]
+    fn invalid_failure_with_non_prefixed_text_lang() {
+        let elem: Element = "<failure xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
+            <not-authorized xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/>
+            <text xmlns='urn:ietf:params:xml:ns:xmpp-sasl' lang='en'>Invalid username or password</text>
+        </failure>"
+            .parse()
+            .unwrap();
+        let failure = Failure::try_from(elem).unwrap();
+        assert_eq!(failure.defined_condition, DefinedCondition::NotAuthorized);
+        assert_eq!(
+            failure.texts[""],
+            String::from("Invalid username or password")
+        );
+    }
 }