diff -urEbwB jdeferred-2.0.0.orig/subprojects/jdeferred-core/src/main/java/org/jdeferred2/impl/FilteredPromise.java jdeferred-2.0.0/subprojects/jdeferred-core/src/main/java/org/jdeferred2/impl/FilteredPromise.java
--- jdeferred-2.0.0.orig/subprojects/jdeferred-core/src/main/java/org/jdeferred2/impl/FilteredPromise.java	2023-09-13 21:53:13.875510018 +0200
+++ jdeferred-2.0.0/subprojects/jdeferred-core/src/main/java/org/jdeferred2/impl/FilteredPromise.java	2023-09-13 22:00:27.086494919 +0200
@@ -29,9 +29,9 @@
 	protected static final NoOpFailFilter NO_OP_FAIL_FILTER = new NoOpFailFilter();
 	protected static final NoOpProgressFilter NO_OP_PROGRESS_FILTER = new NoOpProgressFilter();
 	
-	private final DoneFilter<D, D_OUT> doneFilter;
-	private final FailFilter<F, F_OUT> failFilter;
-	private final ProgressFilter<P, P_OUT> progressFilter;
+	private final DoneFilter<? super D, ? extends D_OUT> doneFilter;
+	private final FailFilter<? super F, ? extends F_OUT> failFilter;
+	private final ProgressFilter<? super P, ? extends P_OUT> progressFilter;
 	
 	public FilteredPromise(final Promise<D, F, P> promise,
 						   final DoneFilter<? super D, ? extends D_OUT> doneFilter,