diff --git a/lib/diaspora_federation/entities/account_migration.rb b/lib/diaspora_federation/entities/account_migration.rb
index 89e19c0..82deed3 100644
--- a/lib/diaspora_federation/entities/account_migration.rb
+++ b/lib/diaspora_federation/entities/account_migration.rb
@@ -43,7 +43,7 @@ module DiasporaFederation
       # Returns diaspora* ID of the new person identity.
       # @return [String] diaspora* ID of the new person identity
       def new_identity
-        profile.author
+        profile.author if profile
       end
 
       # @return [String] string representation of this object
diff --git a/lib/diaspora_federation/validators/conversation_validator.rb b/lib/diaspora_federation/validators/conversation_validator.rb
index d3d63a9..1e66994 100644
--- a/lib/diaspora_federation/validators/conversation_validator.rb
+++ b/lib/diaspora_federation/validators/conversation_validator.rb
@@ -9,7 +9,7 @@ module DiasporaFederation
 
       rule :subject, [:not_empty, length: {maximum: 255}]
 
-      rule :participants, diaspora_id_list: {minimum: 2}
+      rule :participants, [:not_empty, diaspora_id_list: {minimum: 2}]
       rule :messages, :not_nil
     end
   end
diff --git a/lib/diaspora_federation/validators/event_participation_validator.rb b/lib/diaspora_federation/validators/event_participation_validator.rb
index 9bbb9e8..8e1209f 100644
--- a/lib/diaspora_federation/validators/event_participation_validator.rb
+++ b/lib/diaspora_federation/validators/event_participation_validator.rb
@@ -6,7 +6,7 @@ module DiasporaFederation
 
       include RelayableValidator
 
-      rule :status, regular_expression: {regex: /\A(accepted|declined|tentative)\z/}
+      rule :status, [:not_empty, regular_expression: {regex: /\A(accepted|declined|tentative)\z/}]
     end
   end
 end
diff --git a/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
index d493827..bad3334 100644
--- a/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
@@ -27,7 +27,7 @@ module DiasporaFederation
       describe "##{prop}" do
         it_behaves_like "a property with a value validation/restriction" do
           let(:property) { prop }
-          let(:wrong_values) { ["", "https://asdf$%.com", "example.com"] }
+          let(:wrong_values) { %w[https://asdf$.com example.com] }
           let(:correct_values) { [nil] }
         end