diff --git a/src/main.rs b/src/main.rs
index 11d0aee..d981a23 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -192,7 +192,14 @@ fn MainContent() -> impl IntoView {
         level: purl_eval::EvalResultLevel::ProbablyOk,
         explanation: "".to_string(),
     });
-    create_effect(move |_| set_eval_version(purl_eval::eval_purl_version(version())));
+    create_effect(move |_| {
+        set_eval_version(purl_eval::eval_purl_version(
+            typex(),
+            namespace(),
+            name(),
+            version(),
+        ))
+    });
     let (eval_version_result, set_eval_version_result) =
         create_signal(purl_eval::EvalResultLevel::ProbablyOk);
     let (eval_version_result_explanation, set_eval_version_result_explanation) =
@@ -413,6 +420,7 @@ fn MainContent() -> impl IntoView {
                             .into_owned()
                     }
                 />
+
             </div>
             <div class="input-row">
                 <span class="input-label">"qualifiers"</span>
diff --git a/src/purl_eval.rs b/src/purl_eval.rs
index d4ef945..3f185c3 100644
--- a/src/purl_eval.rs
+++ b/src/purl_eval.rs
@@ -229,15 +229,31 @@ pub fn eval_purl_name(
 }
 
 // TODO
-pub fn eval_purl_version(version: Option<String>) -> EvalResult {
+pub fn eval_purl_version(
+    _typex: purl_data::PurlType,
+    _purl_namespace: purl_data::PurlNamespace,
+    _purl_name: String,
+    version: Option<String>,
+) -> EvalResult {
     match version {
         None => EvalResult {
             level: EvalResultLevel::ProbablyOk,
             explanation: "nothing to check on version".to_string(),
         },
         Some(s) => {
-            let mut findings = vec![];
-            EvalResult::aggregate(&findings)
+            match urlencoding::decode(&s) {
+                Err(e) => EvalResult {
+                    level: EvalResultLevel::Invalid,
+                    explanation: format!(
+                        "could not decode, so it must not be a valid percent-encoded string ({e})"
+                    ),
+                },
+                Ok(decoded) => {
+                    let mut findings = vec![];
+                    // TODO
+                    EvalResult::aggregate(&findings)
+                }
+            }
         }
     }
 }