diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Base64BinaryType.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Base64BinaryType.java
index fc0b00ca2..76260ef98 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Base64BinaryType.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/model/Base64BinaryType.java
@@ -99,7 +99,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> {
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.dstu2016may/src/main/java/org/hl7/fhir/dstu2016may/model/Base64BinaryType.java b/org.hl7.fhir.dstu2016may/src/main/java/org/hl7/fhir/dstu2016may/model/Base64BinaryType.java
index 4e5ac9c13..d4a087dd2 100644
--- a/org.hl7.fhir.dstu2016may/src/main/java/org/hl7/fhir/dstu2016may/model/Base64BinaryType.java
+++ b/org.hl7.fhir.dstu2016may/src/main/java/org/hl7/fhir/dstu2016may/model/Base64BinaryType.java
@@ -100,7 +100,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> {
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Base64BinaryType.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Base64BinaryType.java
index 99b7f325d..d21204884 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Base64BinaryType.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/model/Base64BinaryType.java
@@ -152,7 +152,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> implements IPrimitiv
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/Base64BinaryType.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/Base64BinaryType.java
index 7cdceedf7..5b8e67df8 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/Base64BinaryType.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/Base64BinaryType.java
@@ -152,7 +152,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> implements IPrimitiv
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/model/Base64BinaryType.java b/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/model/Base64BinaryType.java
index a1c73f821..6d6ee67da 100644
--- a/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/model/Base64BinaryType.java
+++ b/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/model/Base64BinaryType.java
@@ -156,7 +156,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> implements IPrimitiv
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/Base64BinaryType.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/Base64BinaryType.java
index 4e83d1a8b..1e1650ee8 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/Base64BinaryType.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/Base64BinaryType.java
@@ -156,7 +156,7 @@ public class Base64BinaryType extends PrimitiveType<byte[]> implements IPrimitiv
    * @throws DataFormatException
    */
   public void checkValidBase64(String toCheck) throws DataFormatException {
-    if (!Base64.isBase64(toCheck.getBytes())) {
+    if (!org.hl7.fhir.utilities.Base64.isBase64(toCheck.getBytes())) {
       throw new DataFormatException("");
     }
   }
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Base64.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Base64.java
new file mode 100644
index 000000000..2d5f10767
--- /dev/null
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Base64.java
@@ -0,0 +1,40 @@
+package org.hl7.fhir.utilities;
+
+/**
+ * This is a partial duplication of org.apache.commons.codec.binary.Base64
+ *
+ * It exists because Android compatibility only supports version 1.2 of that
+ * library, which only has the deprecated isArrayByteBase64. The use of
+ * isBase64 from this class will allow us to avoid using a deprecated method
+ * or hacking a solution that involves catching exceptions on decoding.
+ */
+public class Base64 {
+
+  private static final byte[] DECODE_TABLE = new byte[]{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51};
+
+  public static boolean isBase64(byte octet) {
+    return octet == 61 || octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1;
+  }
+
+  public static boolean isBase64(byte[] arrayOctet) {
+    for(int i = 0; i < arrayOctet.length; ++i) {
+      if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  protected static boolean isWhiteSpace(byte byteToCheck) {
+    switch (byteToCheck) {
+      case 9:
+      case 10:
+      case 13:
+      case 32:
+        return true;
+      default:
+        return false;
+    }
+  }
+}
diff --git a/org.hl7.fhir.utilities/src/test/java/Base64Tests.java b/org.hl7.fhir.utilities/src/test/java/Base64Tests.java
new file mode 100644
index 000000000..dab656b98
--- /dev/null
+++ b/org.hl7.fhir.utilities/src/test/java/Base64Tests.java
@@ -0,0 +1,27 @@
+import org.junit.jupiter.api.Test;
+
+import org.hl7.fhir.utilities.Base64;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class Base64Tests {
+  @Test
+  public void testIsArrayByteBase64() {
+    assertFalse(Base64.isBase64(new byte[] { Byte.MIN_VALUE }));
+    assertFalse(Base64.isBase64(new byte[] { -125 }));
+    assertFalse(Base64.isBase64(new byte[] { -10 }));
+    assertFalse(Base64.isBase64(new byte[] { 0 }));
+    assertFalse(Base64.isBase64(new byte[] { 64, Byte.MAX_VALUE }));
+    assertFalse(Base64.isBase64(new byte[] { Byte.MAX_VALUE }));
+
+    assertTrue(Base64.isBase64(new byte[] { 'A' }));
+
+    assertFalse(Base64.isBase64(new byte[] { 'A', Byte.MIN_VALUE }));
+
+    assertTrue(Base64.isBase64(new byte[] { 'A', 'Z', 'a' }));
+    assertTrue(Base64.isBase64(new byte[] { '/', '=', '+' }));
+
+    assertFalse(Base64.isBase64(new byte[] { '$' }));
+  }
+}