diff --git a/frontend_tests/node_tests/people.js b/frontend_tests/node_tests/people.js
index d1047f82ac..2d9c5c0ee7 100644
--- a/frontend_tests/node_tests/people.js
+++ b/frontend_tests/node_tests/people.js
@@ -312,7 +312,7 @@ test_people("basics", () => {
     assert.equal(people.get_non_active_human_ids().length, 1);
     assert.equal(people.get_active_human_count(), 1);
     assert.equal(people.is_active_user_for_popover(isaac.user_id), false);
-    assert.equal(people.is_valid_email_for_compose(isaac.email), false);
+    assert.equal(people.is_valid_email_for_compose(isaac.email), true);
 
     people.add_active_user(bot_botson);
     assert.equal(people.is_active_user_for_popover(bot_botson.user_id), true);
@@ -1077,7 +1077,7 @@ test_people("initialize", () => {
     assert.ok(people.is_cross_realm_email("bot@example.com"));
     assert.ok(people.is_valid_email_for_compose("bot@example.com"));
     assert.ok(people.is_valid_email_for_compose("alice@example.com"));
-    assert.ok(!people.is_valid_email_for_compose("retiree@example.com"));
+    assert.ok(people.is_valid_email_for_compose("retiree@example.com"));
     assert.ok(!people.is_valid_email_for_compose("totally-bogus-username@example.com"));
     assert.ok(people.is_valid_bulk_emails_for_compose(["bot@example.com", "alice@example.com"]));
     assert.ok(!people.is_valid_bulk_emails_for_compose(["not@valid.com", "alice@example.com"]));
diff --git a/frontend_tests/node_tests/top_left_corner.js b/frontend_tests/node_tests/top_left_corner.js
index 0a408b0fa6..ee2340f538 100644
--- a/frontend_tests/node_tests/top_left_corner.js
+++ b/frontend_tests/node_tests/top_left_corner.js
@@ -62,6 +62,12 @@ run_test("narrowing", ({override}) => {
     top_left_corner.handle_narrow_activated(filter);
     assert.ok(!pm_expanded);
 
+    pm_expanded = false;
+    people.deactivate(alice);
+    filter = new Filter([{operator: "pm-with", operand: "alice@example.com"}]);
+    top_left_corner.handle_narrow_activated(filter);
+    assert.ok(pm_expanded);
+
     filter = new Filter([{operator: "is", operand: "mentioned"}]);
     top_left_corner.handle_narrow_activated(filter);
     assert.ok($(".top_left_mentions").hasClass("active-filter"));
diff --git a/static/js/people.js b/static/js/people.js
index b6877a915d..b3e811e1c9 100644
--- a/static/js/people.js
+++ b/static/js/people.js
@@ -730,7 +730,10 @@ export function is_valid_email_for_compose(email) {
     if (!person) {
         return false;
     }
-    return active_user_dict.has(person.user_id);
+
+    // we allow deactivated users in compose so that
+    // one can attempt to reply to threads that contained them.
+    return true;
 }
 
 export function is_valid_bulk_emails_for_compose(emails) {