diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0f1e157..ac74771 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,13 +4,13 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+Nothing to be released.
+
+## [5.2.0] - 2023-04-30
+
 Add Hash ULID generator methods. #25
 Add a MIN and MAX constants and methods. #26
 
-## [5.2.0] - 2023-??-??
-
-To be released.
-
 ## [5.1.0] - 2022-10-22
 
 Add a fast method to generate identifiers. #22
diff --git a/src/main/java/com/github/f4b6a3/ulid/Ulid.java b/src/main/java/com/github/f4b6a3/ulid/Ulid.java
index 29b0d68..740b6d3 100644
--- a/src/main/java/com/github/f4b6a3/ulid/Ulid.java
+++ b/src/main/java/com/github/f4b6a3/ulid/Ulid.java
@@ -89,7 +89,7 @@ public final class Ulid implements Serializable, Comparable<Ulid> {
 	 */
 	public static final Ulid MAX = new Ulid(0xffffffffffffffffL, 0xffffffffffffffffL);
 
-	private static final byte[] ALPHABET_VALUES = new byte[256];
+	protected static final byte[] ALPHABET_VALUES = new byte[256];
 	private static final char[] ALPHABET_UPPERCASE = "0123456789ABCDEFGHJKMNPQRSTVWXYZ".toCharArray();
 	private static final char[] ALPHABET_LOWERCASE = "0123456789abcdefghjkmnpqrstvwxyz".toCharArray();
 
diff --git a/src/main/java/com/github/f4b6a3/ulid/UlidCreator.java b/src/main/java/com/github/f4b6a3/ulid/UlidCreator.java
index bac1633..6c215bf 100644
--- a/src/main/java/com/github/f4b6a3/ulid/UlidCreator.java
+++ b/src/main/java/com/github/f4b6a3/ulid/UlidCreator.java
@@ -104,7 +104,7 @@ public final class UlidCreator {
 	 * <pre>{@code
 	 * long time = file.getCreatedAt();
 	 * String name = file.getFileName();
-	 * Ulid ulid = HashUlid.generate(time, name);
+	 * Ulid ulid = UlidCreator.getHashUlid(time, name);
 	 * }</pre>
 	 * 
 	 * @param time   a number of milliseconds since 1970-01-01 (Unix epoch).
@@ -130,7 +130,7 @@ public final class UlidCreator {
 	 * <pre>{@code
 	 * long time = file.getCreatedAt();
 	 * byte[] bytes = file.getFileBinary();
-	 * Ulid ulid = HashUlid.generate(time, bytes);
+	 * Ulid ulid = UlidCreator.getHashUlid(time, bytes);
 	 * }</pre>
 	 * 
 	 * @param time  a number of milliseconds since 1970-01-01 (Unix epoch).
diff --git a/src/test/java/com/github/f4b6a3/ulid/UlidTest.java b/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
index f1d66e0..62d1349 100644
--- a/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
+++ b/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
@@ -655,6 +655,85 @@ public class UlidTest extends UlidFactoryTest {
 		}
 	}
 
+	@Test
+	public void testAlphabetValues() {
+		byte[] ALPHABET_VALUES = new byte[256];
+		for (int i = 0; i < ALPHABET_VALUES.length; i++) {
+			ALPHABET_VALUES[i] = -1;
+		}
+		// Numbers
+		ALPHABET_VALUES['0'] = 0x00;
+		ALPHABET_VALUES['1'] = 0x01;
+		ALPHABET_VALUES['2'] = 0x02;
+		ALPHABET_VALUES['3'] = 0x03;
+		ALPHABET_VALUES['4'] = 0x04;
+		ALPHABET_VALUES['5'] = 0x05;
+		ALPHABET_VALUES['6'] = 0x06;
+		ALPHABET_VALUES['7'] = 0x07;
+		ALPHABET_VALUES['8'] = 0x08;
+		ALPHABET_VALUES['9'] = 0x09;
+		// Lower case
+		ALPHABET_VALUES['a'] = 0x0a;
+		ALPHABET_VALUES['b'] = 0x0b;
+		ALPHABET_VALUES['c'] = 0x0c;
+		ALPHABET_VALUES['d'] = 0x0d;
+		ALPHABET_VALUES['e'] = 0x0e;
+		ALPHABET_VALUES['f'] = 0x0f;
+		ALPHABET_VALUES['g'] = 0x10;
+		ALPHABET_VALUES['h'] = 0x11;
+		ALPHABET_VALUES['j'] = 0x12;
+		ALPHABET_VALUES['k'] = 0x13;
+		ALPHABET_VALUES['m'] = 0x14;
+		ALPHABET_VALUES['n'] = 0x15;
+		ALPHABET_VALUES['p'] = 0x16;
+		ALPHABET_VALUES['q'] = 0x17;
+		ALPHABET_VALUES['r'] = 0x18;
+		ALPHABET_VALUES['s'] = 0x19;
+		ALPHABET_VALUES['t'] = 0x1a;
+		ALPHABET_VALUES['v'] = 0x1b;
+		ALPHABET_VALUES['w'] = 0x1c;
+		ALPHABET_VALUES['x'] = 0x1d;
+		ALPHABET_VALUES['y'] = 0x1e;
+		ALPHABET_VALUES['z'] = 0x1f;
+		// Lower case OIL
+		ALPHABET_VALUES['o'] = 0x00;
+		ALPHABET_VALUES['i'] = 0x01;
+		ALPHABET_VALUES['l'] = 0x01;
+		// Lower case OIL
+		ALPHABET_VALUES['o'] = 0x00;
+		ALPHABET_VALUES['i'] = 0x01;
+		ALPHABET_VALUES['l'] = 0x01;
+		// Upper case
+		ALPHABET_VALUES['A'] = 0x0a;
+		ALPHABET_VALUES['B'] = 0x0b;
+		ALPHABET_VALUES['C'] = 0x0c;
+		ALPHABET_VALUES['D'] = 0x0d;
+		ALPHABET_VALUES['E'] = 0x0e;
+		ALPHABET_VALUES['F'] = 0x0f;
+		ALPHABET_VALUES['G'] = 0x10;
+		ALPHABET_VALUES['H'] = 0x11;
+		ALPHABET_VALUES['J'] = 0x12;
+		ALPHABET_VALUES['K'] = 0x13;
+		ALPHABET_VALUES['M'] = 0x14;
+		ALPHABET_VALUES['N'] = 0x15;
+		ALPHABET_VALUES['P'] = 0x16;
+		ALPHABET_VALUES['Q'] = 0x17;
+		ALPHABET_VALUES['R'] = 0x18;
+		ALPHABET_VALUES['S'] = 0x19;
+		ALPHABET_VALUES['T'] = 0x1a;
+		ALPHABET_VALUES['V'] = 0x1b;
+		ALPHABET_VALUES['W'] = 0x1c;
+		ALPHABET_VALUES['X'] = 0x1d;
+		ALPHABET_VALUES['Y'] = 0x1e;
+		ALPHABET_VALUES['Z'] = 0x1f;
+		// Upper case OIL
+		ALPHABET_VALUES['O'] = 0x00;
+		ALPHABET_VALUES['I'] = 0x01;
+		ALPHABET_VALUES['L'] = 0x01;
+
+		assertEquals(Arrays.toString(ALPHABET_VALUES), Arrays.toString(Ulid.ALPHABET_VALUES));
+	}
+
 	public static Ulid fromString(String string) {
 
 		long time = 0;