Windows {
	//Existing method. Will be deprecated.
	abstract long size();

	//Existing methods. Will be removed.
	Windows<W> grace(final long millisAfterWindowEnd);
	long gracePeriodMs();

	//New methods.
	abstract Duration size();
	Windows<W> grace(final Duration afterWindowEnd);
	Duration gracePeriod();
}

class Window {
	//Existing methods. Will be deprecated.
	Window(final long startMs, final long endMs) throws IllegalArgumentException;
	long start();
	long end();

	//New methods.
	Window(final Instant start, final Instant end) throws IllegalArgumentException;
	Instant start();
	Instant end();
}

JoinWindows {
    //Existing methods. Will be deprecated.
    static JoinWindows of(final long timeDifferenceMs) throws IllegalArgumentException;
    JoinWindows before(final long timeDifferenceMs) throws IllegalArgumentException;
    JoinWindows after(final long timeDifferenceMs) throws IllegalArgumentException;
    JoinWindows until(final long durationMs) throws IllegalArgumentException;

	//Existing method. Will be removed.
	JoinWindows grace(final long millisAfterWindowEnd);

    //New methods.
    static JoinWindows of(final Duration timeDifference) throws IllegalArgumentException;
    JoinWindows before(final Duration timeDifference) throws IllegalArgumentException;
    JoinWindows after(final Duration timeDifference) throws IllegalArgumentException;
    JoinWindows until(final Duration duration) throws IllegalArgumentException;	
	JoinWindows grace(final Duration afterWindowEnd);
}

Materialized {
	//Existing method. Will be removed.
	Materialized<K, V, S> withRetention(final long retentionMs);

	//New method.
	Materialized<K, V, S> withRetention(final Duration retention);
}


SessionWindows {
	//Existing methods. Will be deprecated.
    static SessionWindows with(final long inactivityGapMs);
    long inactivityGap();

	//Existing methods. Will be removed.
	SessionWindows grace(final long millisAfterWindowEnd);
	long gracePeriodMs();

	//New methods.
    static SessionWindows with(final Duration inactivityGap);
    Duration inactivityGap();
	SessionWindows grace(final Duration afterWindowEnd);
	Duration gracePeriod();
}

TimeWindowedDeserializer {
	//Existing methods. Will be deprecated.
	TimeWindowedDeserializer(final Deserializer<T> inner, final long windowSizeMs);
	Long getWindowSize();

	//New methods.
	TimeWindowedDeserializer(final Deserializer<T> inner, final Duration windowSize);
	Duration getWindowSize();
}

TimeWindows {
	//Existing methods. Will be deprecated.
	static TimeWindows of(final long sizeMs) throws IllegalArgumentException;
	TimeWindows advanceBy(final long advanceMs);
	Map<Long, TimeWindow> windowsFor(final long timestamp);
    long size();

	//Existing method. Will be removed.
	TimeWindows grace(final long millisAfterWindowEnd);

	//New methods.
	static TimeWindows of(final Duration size) throws IllegalArgumentException;
	TimeWindows advanceBy(final Duration advance);
	Map<Long, TimeWindow> windowsFor(final Instant timestamp);
    Duration size();
	TimeWindows grace(final Duration afterWindowEnd);
}

UnlimitedWindows {
	//Existing methods. Will be deprecated.
    UnlimitedWindows startOn(final long startMs) throws IllegalArgumentException;
    Map<Long, UnlimitedWindow> windowsFor(final long timestamp);
	long size();

	//Existing method. Will be removed.
	UnlimitedWindows grace(final long millisAfterWindowEnd);


	//New methods.
    UnlimitedWindows startOn(final Instant start) throws IllegalArgumentException;
    Map<Long, UnlimitedWindow> windowsFor(final Instant timestamp);
	Duration size();
	UnlimitedWindows grace(final Duration afterWindowEnd);
}

ProcessorContext {
    //Existing method. Will be deprecated.
    Cancellable schedule(final long intervalMs,
                         final PunctuationType type,
                         final Punctuator callback);

	//New method.
    Cancellable schedule(final Duration interval,
                         final PunctuationType type,
                         final Punctuator callback);
}

ReadOnlyWindowStore<K, V> {
    //Existing methods. Will be deprecated.
    WindowStoreIterator<V> fetch(K key, long timeFromMs, long timeToMs);
    KeyValueIterator<Windowed<K>, V> fetch(K from, K to, long timeFromMs, long timeToMs);
    KeyValueIterator<Windowed<K>, V> fetchAll(long timeFromMs, long timeToMs);

	//New methods.
    WindowStoreIterator<V> fetch(K key, Instant from, Duration duration);
    KeyValueIterator<Windowed<K>, V> fetch(K from, K to, Instant from, Duration duration);
    KeyValueIterator<Windowed<K>, V> fetchAll(Instant from, Duration duration);
}

SessionBytesStoreSupplier {
    //Existing methods. Will be deprecated.
    long segmentIntervalMs();
    long retentionPeriod();

    //New methods. 
    Duration segmentInterval();
    Duration retentionPeriod();
}

SessionStore {
	//Existing methods. Will be deprecated.
	KeyValueIterator<Windowed<K>, AGG> findSessions(final K key, long earliestSessionEndTimeMs, final long latestSessionStartTimeMs);
	KeyValueIterator<Windowed<K>, AGG> findSessions(final K keyFrom, final K keyTo, long earliestSessionEndTimeMs, final long latestSessionStartTimeMs);

	//New methods.
	KeyValueIterator<Windowed<K>, AGG> findSessions(final K key, Instant earliestSessionEnd, final Instant latestSessionStart);
	KeyValueIterator<Windowed<K>, AGG> findSessions(final K keyFrom, final K keyTo, Instant earliestSessionEnd, final Instant latestSessionStart);
}

Stores {
	//Existing methods. Will be deprecated.
	static WindowBytesStoreSupplier persistentWindowStore(final String name,
    	                                                  final long retentionPeriodMs,
        	                                              final long windowSizeMs,
                                                          final boolean retainDuplicates);

	static WindowBytesStoreSupplier persistentWindowStore(final String name,
                                                          final long retentionPeriodMs,
                                                          final long windowSizeMs,
                                                          final boolean retainDuplicates,
                                                          final long segmentIntervalMs);

	static SessionBytesStoreSupplier persistentSessionStore(final String name,
                                                            final long retentionPeriodMs);

	//New methods.
	static WindowBytesStoreSupplier persistentWindowStore(final String name,
    	                                                  final Duration retentionPeriod,
        	                                              final Duration windowSize,
                                                          final boolean retainDuplicates);

	static WindowBytesStoreSupplier persistentWindowStore(final String name,
                                                          final Duration retentionPeriod,
                                                          final Duration windowSize,
                                                          final boolean retainDuplicates,
                                                          final Duration segmentInterval);

	static SessionBytesStoreSupplier persistentSessionStore(final String name,
                                                            final Duration retentionPeriod);
}

WindowBytesStoreSupplier {
    //Existing methods. Will be deprecated.
    long segmentIntervalMs();
    long windowSize();
    long retentionPeriod();

	//New methods.
    Duration segmentInterval();
    Duration windowSize();
    Duration retentionPeriod();
}

KafkaStreams {
	//Existing method. Will be deprecated.
	public synchronized boolean close(final long timeout, final TimeUnit timeUnit);

	//New method
	public synchronized boolean close(final Duration timeout)
}