diff --git a/build.gradle b/build.gradle
index d9fa0e1f..f74cfbf5 100644
--- a/build.gradle
+++ b/build.gradle
@@ -22,7 +22,7 @@ repositories {
 }
 
 allprojects {
-	version = '1.0.0-RC4'
+	version = '1.0.0-RC5'
 	group = 'it.pagopa.tech.lollipop-consumer-java-sdk'
 	sourceCompatibility = '11'
 	targetCompatibility = '11'
diff --git a/core/src/main/java/it/pagopa/tech/lollipop/consumer/config/LollipopConsumerRequestConfig.java b/core/src/main/java/it/pagopa/tech/lollipop/consumer/config/LollipopConsumerRequestConfig.java
index a3563364..b8ba5bcd 100644
--- a/core/src/main/java/it/pagopa/tech/lollipop/consumer/config/LollipopConsumerRequestConfig.java
+++ b/core/src/main/java/it/pagopa/tech/lollipop/consumer/config/LollipopConsumerRequestConfig.java
@@ -35,8 +35,6 @@ public class LollipopConsumerRequestConfig {
 
     // assertion validation parameters
     @Builder.Default private int assertionExpireInDays = 365;
-    @Builder.Default private String assertionNotBeforeDateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
-    @Builder.Default private String assertionInstantDateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
 
     @Builder.Default
     private String samlNamespaceAssertion = "urn:oasis:names:tc:SAML:2.0:assertion";
diff --git a/core/src/main/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImpl.java b/core/src/main/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImpl.java
index 608cba4c..7c2cfafb 100644
--- a/core/src/main/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImpl.java
+++ b/core/src/main/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImpl.java
@@ -24,11 +24,7 @@
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
 import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Base64;
-import java.util.Date;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.TimeUnit;
 import javax.inject.Inject;
 import javax.xml.parsers.DocumentBuilder;
@@ -37,6 +33,7 @@
 import lombok.extern.slf4j.Slf4j;
 import org.apache.wss4j.common.ext.WSSecurityException;
 import org.apache.wss4j.common.saml.SAMLKeyInfo;
+import org.joda.time.format.ISODateTimeFormat;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
@@ -150,10 +147,8 @@ protected boolean validateAssertionPeriod(Document assertionDoc)
         long notBeforeMilliseconds;
         try {
             notBeforeMilliseconds =
-                    new SimpleDateFormat(lollipopRequestConfig.getAssertionNotBeforeDateFormat())
-                            .parse(notBefore)
-                            .getTime();
-        } catch (ParseException e) {
+                    ISODateTimeFormat.dateTimeParser().parseDateTime(notBefore).getMillis();
+        } catch (UnsupportedOperationException | IllegalArgumentException e) {
             throw new AssertionPeriodException(
                     AssertionPeriodException.ErrorCode.ERROR_PARSING_ASSERTION_NOT_BEFORE_DATE,
                     e.getMessage(),
@@ -442,15 +437,15 @@ private String getPublicKey(String publicKey) {
     }
 
     private String parseInstantToMillis(String instant) {
-        String instantDateFormat = lollipopRequestConfig.getAssertionInstantDateFormat();
         try {
             instant =
-                    Long.toString(new SimpleDateFormat(instantDateFormat).parse(instant).getTime());
-        } catch (ParseException e) {
+                    Long.toString(
+                            ISODateTimeFormat.dateTimeParser().parseDateTime(instant).getMillis());
+        } catch (UnsupportedOperationException | IllegalArgumentException e) {
             String msg =
                     String.format(
-                            "Retrieved instant %s does not match expected format %s",
-                            instant, instantDateFormat);
+                            "Retrieved instant %s does not match expected ISO datetime format",
+                            instant);
             log.debug(msg);
         }
         return instant;
diff --git a/core/src/test/java/it/pagopa/tech/lollipop/consumer/TestUtils.java b/core/src/test/java/it/pagopa/tech/lollipop/consumer/TestUtils.java
index 86161d6a..8e861954 100644
--- a/core/src/test/java/it/pagopa/tech/lollipop/consumer/TestUtils.java
+++ b/core/src/test/java/it/pagopa/tech/lollipop/consumer/TestUtils.java
@@ -26,7 +26,7 @@ public class TestUtils {
                 + " xmlns:saml2=\"urn:oasis:names:tc:SAML:2.0:assertion\""
                 + " ID=\"_6b9580aa-08b1-4f19-8fb6-8b670d070bad\""
                 + " IssueInstant=\"2023-02-28T16:27:25.400Z\" Version=\"2.0\"><saml2:Conditions"
-                + " NotBefore=\"2023-02-28\""
+                + " NotBefore=\"2023-02-28Z\""
                 + " NotOnOrAfter=\"2023-02-28T16:28:25.400Z\"><saml2:AudienceRestriction><saml2:Audience>https://app-backend.io.italia.it</saml2:Audience></saml2:AudienceRestriction></saml2:Conditions></saml2:Assertion></saml2p:Response>";
     public static final String ASSERTION_XML_WITH_EXPIRED_PERIOD =
             "<?xml version=\"1.0\" encoding=\"UTF-8\"?><saml2p:Response"
diff --git a/core/src/test/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImplTest.java b/core/src/test/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImplTest.java
index 3e681c7d..15d684b2 100644
--- a/core/src/test/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImplTest.java
+++ b/core/src/test/java/it/pagopa/tech/lollipop/consumer/service/impl/AssertionVerifierServiceImplTest.java
@@ -190,9 +190,6 @@ void validateLollipopValidatePeriodSuccess() {
         assertion.setAssertionData(VALID_ASSERTION_XML);
 
         doReturn(365 * 20).when(lollipopRequestConfigMock).getAssertionExpireInDays();
-        doReturn("yyyy-MM-dd'T'HH:mm:ss'Z'")
-                .when(lollipopRequestConfigMock)
-                .getAssertionNotBeforeDateFormat();
 
         doReturn(assertion).when(assertionServiceMock).getAssertion(anyString(), anyString());
         doReturn(true)
diff --git a/samples/simple/build.gradle b/samples/simple/build.gradle
index f8c1aa52..e5e0d03a 100644
--- a/samples/simple/build.gradle
+++ b/samples/simple/build.gradle
@@ -13,7 +13,7 @@ plugins {
 
 
 group = 'it.pagopa.tech.lollipop.consumer.samples'
-version = '1.0.0-RC4'
+version = '1.0.0-RC5'
 sourceCompatibility = '11'
 
 application {
diff --git a/samples/spring/build.gradle b/samples/spring/build.gradle
index 9ff07bfa..e83052d6 100644
--- a/samples/spring/build.gradle
+++ b/samples/spring/build.gradle
@@ -5,7 +5,7 @@ plugins {
 }
 
 group = 'it.pagopa.tech.lollipop.consumer.samples'
-version = '1.0.0-RC4'
+version = '1.0.0-RC5'
 sourceCompatibility = '11'
 
 configurations {
diff --git a/servlet-impl/src/test/java/it/pagopa/tech/lollipop/consumer/servlet/ServletIntegrationTest.java b/servlet-impl/src/test/java/it/pagopa/tech/lollipop/consumer/servlet/ServletIntegrationTest.java
index ce3dadda..fa7cdc95 100644
--- a/servlet-impl/src/test/java/it/pagopa/tech/lollipop/consumer/servlet/ServletIntegrationTest.java
+++ b/servlet-impl/src/test/java/it/pagopa/tech/lollipop/consumer/servlet/ServletIntegrationTest.java
@@ -64,8 +64,6 @@ void testWithAValidRequestReturnsSuccess() throws IOException {
         SimpleClientsTestUtils.createExpectationAssertionFound();
         SimpleClientsTestUtils.createExpectationIdpFound();
         lollipopConsumerRequestConfig.setAssertionExpireInDays(365);
-        lollipopConsumerRequestConfig.setAssertionNotBeforeDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
-        lollipopConsumerRequestConfig.setAssertionInstantDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
 
         RestTemplate exec = restTemplate.getRestTemplate();
         exec.getClientHttpRequestInitializers()
diff --git a/spring-impl/src/test/java/it/pagopa/tech/lollipop/consumer/spring/HttpVerifierHandlerInterceptorIntegrationTest.java b/spring-impl/src/test/java/it/pagopa/tech/lollipop/consumer/spring/HttpVerifierHandlerInterceptorIntegrationTest.java
index 7e1d3cbe..8456bf06 100644
--- a/spring-impl/src/test/java/it/pagopa/tech/lollipop/consumer/spring/HttpVerifierHandlerInterceptorIntegrationTest.java
+++ b/spring-impl/src/test/java/it/pagopa/tech/lollipop/consumer/spring/HttpVerifierHandlerInterceptorIntegrationTest.java
@@ -60,10 +60,6 @@ public void startServer() {
     void testWithValidRequestReturnsSuccess() throws IOException {
         SimpleClientsTestUtils.createExpectationAssertionFound();
         SimpleClientsTestUtils.createExpectationIdpFound();
-        springLollipopConsumerRequestConfig.setAssertionNotBeforeDateFormat(
-                "yyyy-MM-dd'T'HH:mm:ss'Z'");
-        springLollipopConsumerRequestConfig.setAssertionInstantDateFormat(
-                "yyyy-MM-dd'T'HH:mm:ss'Z'");
 
         RestTemplate exec = restTemplate.getRestTemplate();
         exec.getClientHttpRequestInitializers()
@@ -202,10 +198,6 @@ void testWithInvalidURLRequestReturnsUnauthorized() throws IOException {
         SimpleClientsTestUtils.createExpectationAssertionFound();
         SimpleClientsTestUtils.createExpectationIdpFound();
         springLollipopConsumerRequestConfig.setAssertionExpireInDays(365);
-        springLollipopConsumerRequestConfig.setAssertionNotBeforeDateFormat(
-                "yyyy-MM-dd'T'HH:mm:ss'Z'");
-        springLollipopConsumerRequestConfig.setAssertionInstantDateFormat(
-                "yyyy-MM-dd'T'HH:mm:ss'Z'");
         idpCertSimpleClientConfig.setBaseUri("http://localhost:3001");
 
         RestTemplate exec = restTemplate.getRestTemplate();