Remove info about older JDKs

Author: tvernum

docs/reference/security/securing-communications/tls-versions-jdk.asciidoc

@@ -33,13 +33,8 @@ TLS v1.2 is supported on all {es} <<jvm-version,compatible JDKs>>.
 It is enabled by default on all JDKs that are supported by {es}, including the bundled JDK.
 
 `TLSv1.3`::
-TLS v1.3 is supported on JDK11 and later, and JDK8 builds newer than 8u261
-(including the most recent release of each JDK8 distribution that {es} supports).
-TLS v1.3 is supported and enabled by default on the JDK that is bundled with {es}.
-+
-NOTE: Although {es} supports running on older JDK8 builds without TLS v1.3,
-we recommend upgrading to a JDK version that includes TLS v1.3 for better
-support and updates.
+TLS v1.3 is supported on all {es} <<jvm-version,compatible JDKs>>.
+It is enabled by default on all JDKs that are supported by {es}, including the bundled JDK.
 
 [[jdk-enable-tls-protocol]]
 ==== Enabling additional SSL/TLS versions on your JDK
@@ -67,13 +62,6 @@ the {es} home directory (`$ES_HOME`):
 * Windows: `$ES_HOME/jdk/conf/security/java.security`
 * macOS:`$ES_HOME/jdk.app/Contents/Home/conf/security/java.security`
 
-For **JDK8**, the configuration file is within the `jre/lib/security` directory
-of the Java installation.
-If `$JAVA_HOME` points to the home directory of the JDK that you use to run {es},
-then the configuration file will be in:
-
-* `$JAVA_HOME/jre/lib/security/java.security`
-
 For **JDK11 or later**, the configuration file is within the `conf/security`
 directory of the Java installation.
 If `$JAVA_HOME` points to the home directory of the JDK that you use to run
@@ -88,11 +76,12 @@ Within the JDK configuration file is a line that starts with
 This setting controls which protocols and algorithms are _disabled_ in your JDK.
 The value of that setting will typically span multiple lines.
 
-For example, in OpenJDK 16 the setting is:
+For example, in OpenJDK 21 the setting is:
 [source,text]
 --------------------------------------------------
-jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, \
-    DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL
+jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, DTLSv1.0, RC4, DES, \
+    MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
+    ECDH
 --------------------------------------------------
 
 Create a new file in your in your {es} configuration directory named `es.java.security`.
@@ -105,15 +94,16 @@ Edit the `es.java.security` file in your {es} configuration directory, and
 modify the `jdk.tls.disabledAlgorithms` setting so that any SSL or TLS versions
 that you wish to use are no longer listed.
 
-For example, to enable TLSv1.1 on OpenJDK 16 (which uses the
+For example, to enable TLSv1.1 on OpenJDK 21 (which uses the
 `jdk.tls.disabledAlgorithms` settings shown previously), the
 `es.java.security` file would contain the previously disabled TLS algorithms
 _except_ `TLSv1.1`:
 
 [source,text]
 --------------------------------------------------
-jdk.tls.disabledAlgorithms=SSLv3, TLSv1, RC4, DES, MD5withRSA, \
-    DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL
+jdk.tls.disabledAlgorithms=SSLv3, TLSv1, DTLSv1.0, RC4, DES, \
+    MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
+    ECDH
 --------------------------------------------------
 
 ===== Enable your custom security configuration