diff --git a/log4j-api/pom.xml b/log4j-api/pom.xml
index 5db39f09bdd..249887921c7 100644
--- a/log4j-api/pom.xml
+++ b/log4j-api/pom.xml
@@ -29,6 +29,7 @@
   <description>The Apache Log4j API</description>
   <properties>
     <maven.javadoc.skip>false</maven.javadoc.skip>
+    <bnd.baseline.skip>false</bnd.baseline.skip>
 
     <!--
       ~ OSGi and JPMS options
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/Level.java b/log4j-api/src/main/java/org/apache/logging/log4j/Level.java
index 221f88c9a38..02c7d2f7505 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/Level.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/Level.java
@@ -18,6 +18,7 @@
 
 import static org.apache.logging.log4j.util.Strings.toRootUpperCase;
 
+import aQute.bnd.annotation.baseline.BaselineIgnore;
 import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -71,6 +72,7 @@
  * used in logging configurations.
  * </p>
  */
+@BaselineIgnore("3.0.0")
 public final class Level implements Comparable<Level> {
 
     private static final Level[] EMPTY_ARRAY = {};
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java b/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
index 334ee5fd59d..aa16353407c 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/LogManager.java
@@ -40,7 +40,13 @@
 public class LogManager {
 
     /**
-     * Constant holding the name of the root logger (the empty string).
+     * Kept for binary compatibility.
+     */
+    @Deprecated(forRemoval = true)
+    public static final String FACTORY_PROPERTY_NAME = "log4j2.loggerContextFactory";
+
+    /**
+     * The name of the root Logger is {@value #ROOT_LOGGER_NAME}.
      */
     public static final String ROOT_LOGGER_NAME = Strings.EMPTY;
 
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/Logger.java b/log4j-api/src/main/java/org/apache/logging/log4j/Logger.java
index 680234bdabf..2ca3b07132c 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/Logger.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/Logger.java
@@ -122,6 +122,7 @@ public interface Logger {
      * @param messageSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
+    @SuppressWarnings("removal")
     void debug(Marker marker, MessageSupplier messageSupplier);
 
     /**
@@ -134,6 +135,7 @@ public interface Logger {
      * @param throwable A Throwable or null.
      * @since 2.4
      */
+    @SuppressWarnings("removal")
     void debug(Marker marker, MessageSupplier messageSupplier, Throwable throwable);
 
     /**
@@ -199,7 +201,7 @@ public interface Logger {
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -221,7 +223,7 @@ public interface Logger {
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -234,7 +236,7 @@ public interface Logger {
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -328,7 +330,7 @@ public interface Logger {
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -347,7 +349,7 @@ public interface Logger {
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(Supplier<?> messageSupplier);
 
     /**
@@ -359,7 +361,7 @@ public interface Logger {
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void debug(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -677,6 +679,40 @@ void debug(
             Object p8,
             Object p9);
 
+    /**
+     * Logs entry to a method. Used when the method in question has no parameters or when the parameters should not be
+     * logged.
+     * @deprecated Use {@link #traceEntry()} instead which performs the same function.
+     */
+    @Deprecated(forRemoval = true, since = "2.6")
+    default void entry() {
+        traceEntry();
+    }
+
+    /**
+     * Logs entry to a method along with its parameters (consider using one of the {@code traceEntry(...)} methods instead.)
+     * <p>
+     * For example:
+     * </p>
+     * <pre>
+     * public void doSomething(String foo, int bar) {
+     *     LOGGER.entry(foo, bar);
+     *     // do something
+     * }
+     * </pre>
+     * <p>
+     * The use of methods such as this are more effective when combined with aspect-oriented programming or other
+     * bytecode manipulation tools. It can be rather tedious (and messy) to use this type of method manually.
+     * </p>
+     *
+     * @param params The parameters to the method.
+     * @deprecated Use {@link #traceEntry(String, Object...)} instead which performs the same function.
+     */
+    @Deprecated(forRemoval = true, since = "2.12")
+    default void entry(final Object... params) {
+        traceEntry(null, params);
+    }
+
     /**
      * Logs a message with the specific Marker at the {@link Level#ERROR ERROR} level.
      *
@@ -780,7 +816,7 @@ void debug(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -802,7 +838,7 @@ void debug(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -815,7 +851,7 @@ void debug(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -909,7 +945,7 @@ void debug(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -928,7 +964,7 @@ void debug(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(Supplier<?> messageSupplier);
 
     /**
@@ -940,7 +976,7 @@ void debug(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void error(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1258,6 +1294,32 @@ void error(
             Object p8,
             Object p9);
 
+    /**
+     * Logs exit from a method. Used for methods that do not return anything.
+     * @deprecated Use {@link #traceExit()} instead which performs the same function.
+     */
+    @Deprecated(forRemoval = true, since = "2.6")
+    default void exit() {
+        traceExit();
+    }
+
+    /**
+     * Logs exiting from a method with the result. This may be coded as:
+     *
+     * <pre>
+     * return LOGGER.exit(myResult);
+     * </pre>
+     *
+     * @param <R> The type of the parameter and object being returned.
+     * @param result The result being returned from the method call.
+     * @return the result.
+     * @deprecated Use {@link #traceExit(Object)} instead which performs the same function.
+     */
+    @Deprecated(forRemoval = true, since = "2.6")
+    default <R> R exit(final R result) {
+        return traceExit(result);
+    }
+
     /**
      * Logs a message with the specific Marker at the {@link Level#FATAL FATAL} level.
      *
@@ -1361,7 +1423,7 @@ void error(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -1383,7 +1445,7 @@ void error(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -1396,7 +1458,7 @@ void error(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1490,7 +1552,7 @@ void error(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -1509,7 +1571,7 @@ void error(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(Supplier<?> messageSupplier);
 
     /**
@@ -1521,7 +1583,7 @@ void error(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void fatal(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -1977,7 +2039,7 @@ void fatal(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -1999,7 +2061,7 @@ void fatal(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -2012,7 +2074,7 @@ void fatal(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2106,7 +2168,7 @@ void fatal(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2125,7 +2187,7 @@ void fatal(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(Supplier<?> messageSupplier);
 
     /**
@@ -2137,7 +2199,7 @@ void fatal(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void info(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2684,7 +2746,7 @@ void info(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2707,7 +2769,7 @@ void info(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -2721,7 +2783,7 @@ void info(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -2825,7 +2887,7 @@ void info(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -2846,7 +2908,7 @@ void info(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, Supplier<?> messageSupplier);
 
     /**
@@ -2859,7 +2921,7 @@ void info(
      * @param throwable the {@code Throwable} to log, including its stack log.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void log(Level level, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3382,7 +3444,7 @@ void log(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -3405,7 +3467,7 @@ void log(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -3418,7 +3480,7 @@ void log(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3514,7 +3576,7 @@ void log(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -3534,7 +3596,7 @@ void log(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(Supplier<?> messageSupplier);
 
     /**
@@ -3546,7 +3608,7 @@ void log(
      * @param throwable the {@code Throwable} to log, including its stack trace.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void trace(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -3914,7 +3976,7 @@ void trace(
      *
      * @since 2.6
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     EntryMessage traceEntry(Supplier<?>... paramSuppliers);
 
     /**
@@ -3933,7 +3995,7 @@ void trace(
      *
      * @since 2.6
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     EntryMessage traceEntry(String format, Supplier<?>... paramSuppliers);
 
     /**
@@ -4152,7 +4214,7 @@ void trace(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -4174,7 +4236,7 @@ void trace(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(Marker marker, Supplier<?> messageSupplier);
 
     /**
@@ -4187,7 +4249,7 @@ void trace(
      * @param throwable A Throwable or null.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(Marker marker, Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -4281,7 +4343,7 @@ void trace(
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -4300,7 +4362,7 @@ void trace(
      *            message factory.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(Supplier<?> messageSupplier);
 
     /**
@@ -4312,7 +4374,7 @@ void trace(
      * @param throwable the {@code Throwable} to log, including its stack warn.
      * @since 2.4
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void warn(Supplier<?> messageSupplier, Throwable throwable);
 
     /**
@@ -4642,7 +4704,12 @@ void warn(
      * @since 2.13.0
      */
     default void logMessage(
-            Level level, Marker marker, String fqcn, StackTraceElement location, Message message, Throwable throwable) {
+            final Level level,
+            final Marker marker,
+            final String fqcn,
+            final StackTraceElement location,
+            final Message message,
+            final Throwable throwable) {
         // noop
     }
 
@@ -4715,7 +4782,7 @@ default LogBuilder always() {
      * @return a LogBuilder.
      * @since 2.13.0
      */
-    default LogBuilder atLevel(Level level) {
+    default LogBuilder atLevel(final Level level) {
         return LogBuilder.NOOP;
     }
 }
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/Marker.java b/log4j-api/src/main/java/org/apache/logging/log4j/Marker.java
index 18e2728423a..049a12df4b7 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/Marker.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/Marker.java
@@ -16,6 +16,8 @@
  */
 package org.apache.logging.log4j;
 
+import aQute.bnd.annotation.baseline.BaselineIgnore;
+
 /**
  * Markers are objects that are used to add easily filterable information to log messages.
  *
@@ -23,6 +25,7 @@
  * more specific categories. An example might be a Marker named "Error" with children named "SystemError" and
  * "ApplicationError".
  */
+@BaselineIgnore("3.0.0")
 public interface Marker {
 
     /**
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/MarkerManager.java b/log4j-api/src/main/java/org/apache/logging/log4j/MarkerManager.java
index 8cd49c3f45d..f64ed2b3861 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/MarkerManager.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/MarkerManager.java
@@ -16,6 +16,7 @@
  */
 package org.apache.logging.log4j;
 
+import aQute.bnd.annotation.baseline.BaselineIgnore;
 import java.util.Arrays;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -80,6 +81,7 @@ public static Marker getMarker(final String name) {
      * is moved to this package and would of course stay in its current module.</em>
      * </p>
      */
+    @BaselineIgnore("3.0.0")
     public static class Log4jMarker implements Marker, StringBuilderFormattable {
 
         private final String name;
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/ThreadContext.java b/log4j-api/src/main/java/org/apache/logging/log4j/ThreadContext.java
index e5a3056b6d5..8a5a6a6b183 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/ThreadContext.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/ThreadContext.java
@@ -16,6 +16,7 @@
  */
 package org.apache.logging.log4j;
 
+import aQute.bnd.annotation.baseline.BaselineIgnore;
 import java.util.AbstractCollection;
 import java.util.Collection;
 import java.util.Collections;
@@ -498,6 +499,7 @@ public static void trim(final int depth) {
     /**
      * The ThreadContext Stack interface.
      */
+    @BaselineIgnore("3.0.0")
     public interface ContextStack extends Collection<String> {
 
         /**
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/message/AbstractMessageFactory.java b/log4j-api/src/main/java/org/apache/logging/log4j/message/AbstractMessageFactory.java
index 7b5db98a655..cfefaded66d 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/message/AbstractMessageFactory.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/message/AbstractMessageFactory.java
@@ -22,5 +22,5 @@
  *
  * @deprecated MessageFactory has default methods that implement all the methods that were here.
  */
-@Deprecated
+@Deprecated(forRemoval = true, since = "3.0")
 public abstract class AbstractMessageFactory implements MessageFactory {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/message/Clearable.java b/log4j-api/src/main/java/org/apache/logging/log4j/message/Clearable.java
index 596dc773546..512f631c385 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/message/Clearable.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/message/Clearable.java
@@ -21,7 +21,7 @@
  *
  * @deprecated use {@link ReusableMessage} directly
  */
-@Deprecated(since = "3.0.0")
+@Deprecated(forRemoval = true, since = "3.0")
 interface Clearable {
 
     /**
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/message/MessageFactory2.java b/log4j-api/src/main/java/org/apache/logging/log4j/message/MessageFactory2.java
index 23b280ab123..5cdbb61cc82 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/message/MessageFactory2.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/message/MessageFactory2.java
@@ -22,5 +22,5 @@
  * @deprecated MessageFactory now contains all interface methods.
  * @since 2.6
  */
-@Deprecated
+@Deprecated(forRemoval = true, since = "3.0")
 public interface MessageFactory2 extends MessageFactory {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/package-info.java b/log4j-api/src/main/java/org/apache/logging/log4j/package-info.java
index 2af24bdd749..26d0060c1b5 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/package-info.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/package-info.java
@@ -29,6 +29,11 @@
  *     used through the {@link org.apache.logging.log4j.ThreadContext} class.
  * </p>
  *
+ *<p>
+ * <strong>Version 3.x note:</strong> the only backward incompatible change in this package is
+ * the removal of serializability.
+ * </p>
+ *
  * @see <a href="http://logging.apache.org/log4j/2.x/manual/api.html">Log4j 2 API manual</a>
  */
 @Export
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/CleanableThreadContextMap.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/CleanableThreadContextMap.java
index a9447851556..9da75e5a376 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/CleanableThreadContextMap.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/CleanableThreadContextMap.java
@@ -24,5 +24,5 @@
  * @since 2.8
  * @deprecated use {@link ThreadContextMap} directly
  */
-@Deprecated(since = "3.0.0")
+@Deprecated(forRemoval = true, since = "3.0")
 public interface CleanableThreadContextMap extends ThreadContextMap2 {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ExtendedLogger.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ExtendedLogger.java
index 29b02cf53df..a24cfd33aab 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ExtendedLogger.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ExtendedLogger.java
@@ -26,6 +26,9 @@
 /**
  * Extends the {@code Logger} interface with methods that facilitate implementing or extending {@code Logger}s. Users
  * should not need to use this interface.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link LoggerContext#getLogger(String)}.
+ * </p>
  */
 public interface ExtendedLogger extends Logger {
 
@@ -634,6 +637,7 @@ void logIfEnabled(
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      */
+    @SuppressWarnings("removal")
     void logIfEnabled(String fqcn, Level level, Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
@@ -646,7 +650,7 @@ void logIfEnabled(
      * @param message The message format.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void logIfEnabled(String fqcn, Level level, Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
@@ -659,6 +663,6 @@ void logIfEnabled(
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      */
-    @SuppressWarnings("deprecation")
+    @SuppressWarnings("removal")
     void logIfEnabled(String fqcn, Level level, Marker marker, Supplier<?> msgSupplier, Throwable t);
 }
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContext.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContext.java
index 159914c39b3..01cd966c084 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContext.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContext.java
@@ -16,6 +16,7 @@
  */
 package org.apache.logging.log4j.spi;
 
+import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.MessageFactory;
 import org.apache.logging.log4j.util.PropertiesUtil;
@@ -23,6 +24,9 @@
 
 /**
  * Anchor point for logging implementations.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link LogManager#getContext()}
+ * </p>
  */
 public interface LoggerContext {
 
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContextFactory.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContextFactory.java
index 0a33d27ced4..c30a54a1949 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContextFactory.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerContextFactory.java
@@ -17,9 +17,13 @@
 package org.apache.logging.log4j.spi;
 
 import java.net.URI;
+import org.apache.logging.log4j.LogManager;
 
 /**
  * Implemented by factories that create {@link LoggerContext} objects.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link LogManager#getFactory()}
+ * </p>
  */
 public interface LoggerContextFactory {
 
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerRegistry.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerRegistry.java
index 8d253252420..7a454d8b6d5 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerRegistry.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/LoggerRegistry.java
@@ -26,6 +26,9 @@
 
 /**
  * Convenience class to be used by {@code LoggerContext} implementations.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link LoggerContext#getLoggerRegistry()}.
+ * </p>
  */
 public class LoggerRegistry<T extends ExtendedLogger> {
     private final MapFactory<T> factory;
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ObjectThreadContextMap.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ObjectThreadContextMap.java
index 4eae4736cb0..beda028b4c7 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ObjectThreadContextMap.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ObjectThreadContextMap.java
@@ -24,5 +24,5 @@
  * @since 2.8
  * @deprecated use {@link ThreadContextMap} directly
  */
-@Deprecated(since = "3.0.0")
+@Deprecated(forRemoval = true, since = "3.0")
 public interface ObjectThreadContextMap extends CleanableThreadContextMap {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ReadOnlyThreadContextMap.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ReadOnlyThreadContextMap.java
index de9ae028aa2..aafbacfeb83 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ReadOnlyThreadContextMap.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ReadOnlyThreadContextMap.java
@@ -25,8 +25,9 @@
  * <p>
  * {@code ThreadContextMap} implementations that also implement this interface can be accessed
  * by applications via the {@link ThreadContext#getThreadContextMap()} method.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link ThreadContext#getThreadContextMap()}.
  * </p>
- *
  * @see ThreadContext#getThreadContextMap()
  * @since 2.8
  */
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/StandardLevel.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/StandardLevel.java
index c08d7177abc..2ecd035e959 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/StandardLevel.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/StandardLevel.java
@@ -17,9 +17,13 @@
 package org.apache.logging.log4j.spi;
 
 import java.util.EnumSet;
+import org.apache.logging.log4j.Level;
 
 /**
  * Standard Logging Levels as an enumeration for use internally. This enum is used as a parameter in any public APIs.
+ * <p>
+ *     <strong>Warning:</strong> part of the API, not the SPI, since it is used by {@link Level#getStandardLevel()}.
+ * </p>
  */
 public enum StandardLevel {
 
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ThreadContextMap2.java b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ThreadContextMap2.java
index 3e4e248323f..35841feb4a2 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/spi/ThreadContextMap2.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/spi/ThreadContextMap2.java
@@ -24,5 +24,5 @@
  * @since 2.7
  * @deprecated use {@link ThreadContextMap} directly
  */
-@Deprecated(since = "3.0.0")
+@Deprecated(forRemoval = true, since = "3.0")
 public interface ThreadContextMap2 extends ThreadContextMap {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/BiConsumer.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/BiConsumer.java
index 9987a098085..81a67b3b33c 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/BiConsumer.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/BiConsumer.java
@@ -18,12 +18,15 @@
 
 /**
  * An operation that accepts two input arguments and returns no result.
- *
+ * <p>
+ *     <strong>Warning:</strong> part of the public API, since it is used by {@link ReadOnlyStringMap#forEach(BiConsumer)}.
+ * </p>
  * @param <K> type of the first argument
  * @param <V> type of the second argument
  * @see ReadOnlyStringMap
  * @since 2.7
  */
+@Deprecated(forRemoval = true, since = "3.0")
 public interface BiConsumer<K, V> extends java.util.function.BiConsumer<K, V> {
 
     /**
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/MessageSupplier.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/MessageSupplier.java
index 73d39a6128a..2904668e151 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/MessageSupplier.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/MessageSupplier.java
@@ -16,6 +16,7 @@
  */
 package org.apache.logging.log4j.util;
 
+import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.message.Message;
 
 /**
@@ -26,11 +27,10 @@
  *
  * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.
  *
- * <p><strong>DEPRECATED:</strong> this class should not normally be used outside a Java 8+ lambda syntax. Instead,
- * {@link Supplier Supplier&lt;Message&gt;} should be used as an anonymous class. Both this and {@link Supplier} will be
- * removed in 3.0.
+ * <p>
+ *     <strong>Warning:</strong> part of the public API, since it is used by {@link org.apache.logging.log4j.Logger#debug(Marker, MessageSupplier)}.
  * </p>
- *
  * @since 2.4
  */
+@Deprecated(forRemoval = true, since = "3.0")
 public interface MessageSupplier extends java.util.function.Supplier<Message> {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/ReadOnlyStringMap.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/ReadOnlyStringMap.java
index 860a1782a8f..c1809b00a12 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/ReadOnlyStringMap.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/ReadOnlyStringMap.java
@@ -20,7 +20,9 @@
 
 /**
  * A read-only collection of String keys mapped to values of arbitrary type.
- *
+ * <p>
+ *     <strong>Warning:</strong> part of the API, since it is used by {@link StringMap}.
+ * </p>
  * @since 2.7
  */
 public interface ReadOnlyStringMap {
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/StringBuilderFormattable.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/StringBuilderFormattable.java
index fa8d5c28893..7999cb25549 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/StringBuilderFormattable.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/StringBuilderFormattable.java
@@ -18,7 +18,9 @@
 
 /**
  * Objects that implement this interface can be converted to text, ideally without allocating temporary objects.
- *
+ * <p>
+ *     <strong>Warning:</strong> part of the API, since it is used by {@link org.apache.logging.log4j.MarkerManager.Log4jMarker}.
+ * </p>
  * @since 2.6
  */
 public interface StringBuilderFormattable {
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/StringMap.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/StringMap.java
index 6d4ef39f931..293e8a71ca4 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/StringMap.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/StringMap.java
@@ -16,9 +16,13 @@
  */
 package org.apache.logging.log4j.util;
 
+import org.apache.logging.log4j.spi.ReadOnlyThreadContextMap;
+
 /**
  * Exposes methods to add and remove key-value pairs to and from {@code ReadOnlyStringMap}.
- *
+ * <p>
+ *     <strong>Warning:</strong> part of the API, since it is used by {@link ReadOnlyThreadContextMap#getReadOnlyContextData()}.
+ * </p>
  * @see ReadOnlyStringMap
  * @since 2.7
  */
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/Supplier.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/Supplier.java
index 17f2603f683..c207f0076ec 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/Supplier.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/Supplier.java
@@ -25,11 +25,11 @@
  *
  * <p>Implementors are free to cache values or return a new or distinct value each time the supplier is invoked.
  *
- * <p><strong>DEPRECATED:</strong> this class will be removed in 3.0 to be replaced with the Java 8 interface.</p>
+ * <p><strong>DEPRECATED:</strong> this class is deprecated and will be replaced with the Java 8 interface.</p>
  *
  * @param <T> the type of values returned by this supplier
  *
  * @since 2.4
  */
-@Deprecated
+@Deprecated(forRemoval = true, since = "2.22")
 public interface Supplier<T> extends java.util.function.Supplier<T> {}
diff --git a/log4j-api/src/main/java/org/apache/logging/log4j/util/TriConsumer.java b/log4j-api/src/main/java/org/apache/logging/log4j/util/TriConsumer.java
index f307dada6e7..b70c7b4caa7 100644
--- a/log4j-api/src/main/java/org/apache/logging/log4j/util/TriConsumer.java
+++ b/log4j-api/src/main/java/org/apache/logging/log4j/util/TriConsumer.java
@@ -18,7 +18,9 @@
 
 /**
  * An operation that accepts three input arguments and returns no result.
- *
+ * <p>
+ *     <strong>Warning:</strong> part of the public API, since it is used by {@link ReadOnlyStringMap#forEach(TriConsumer, Object)}.
+ * </p>
  * @param <K> type of the first argument
  * @param <V> type of the second argument
  * @param <S> type of the third argument
diff --git a/log4j-api/src/main/resources/log4j2.propertyMapping.json b/log4j-api/src/main/resources/log4j2.propertyMapping.json
index 5edb3f7bf90..e338ca1148a 100644
--- a/log4j-api/src/main/resources/log4j2.propertyMapping.json
+++ b/log4j-api/src/main/resources/log4j2.propertyMapping.json
@@ -11,6 +11,7 @@
     "isWebapp": ["Web", "isWebApp"],
     "is.webapp": ["Web", "isWebApp"],
     "level": ["Configuration", "level"],
+    "loggerContextFactory": ["LoggerContext", "factory"],
     "maxReusableMsgSize": ["GC", "maxReusableMsgSize"],
     "messageFactory": ["Message", "Factory"],
     "simplelogDateTimeFormat": ["SimpleLogger", "dateTimeFormat"],
@@ -41,6 +42,7 @@
     "IS_THREAD_CONTEXT_MAP_INHERITABLE": ["ThreadContext", "inheritable"],
     "IS_WEBAPP": ["WEB", "isWebApp"],
     "LEVEL": ["Configuration", "level"],
+    "LOGGER_CONTEXT_FACTORY": ["LoggerContext", "factory"],
     "MAX_REUSABLE_MSG_SIZE": ["GC", "maxReusableMsgSize"],
     "MESSAGE_FACTORY": ["Message", "Factory"],
     "SIMPLELOG_DATE_TIME_FORMAT": ["SimpleLogger", "dateTimeFormat"],