Renable bwc and update version checks after merging elastic#72754

Author: andreidan

build.gradle

@@ -196,9 +196,9 @@ tasks.register("verifyVersions") {
  * after the backport of the backcompat code is complete.
  */
 
-boolean bwc_tests_enabled = false
+boolean bwc_tests_enabled = true
 // place a PR link here when committing bwc changes:
-String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/67861"
+String bwc_tests_disabled_issue = ""
 /*
  * FIPS 140-2 behavior was fixed in 7.11.0. Before that there is no way to run elasticsearch in a
  * JVM that is properly configured to be in fips mode with BCFIPS. For now we need to disable

server/src/main/java/org/elasticsearch/monitor/fs/FsInfo.java

@@ -237,12 +237,12 @@ public DeviceStats(StreamInput in) throws IOException {
             previousSectorsRead = in.readLong();
             currentSectorsWritten = in.readLong();
             previousSectorsWritten = in.readLong();
-            if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (in.getVersion().onOrAfter(Version.V_7_14_0)) {
                 currentIOTime = in.readLong();
                 previousIOTime = in.readLong();
             } else {
-                currentIOTime = 0;
-                previousIOTime = 0;
+                currentIOTime = -1;
+                previousIOTime = -1;
             }
         }
 
@@ -259,7 +259,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(previousSectorsRead);
             out.writeLong(currentSectorsWritten);
             out.writeLong(previousSectorsWritten);
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (out.getVersion().onOrAfter(Version.V_7_14_0)) {
                 out.writeLong(currentIOTime);
                 out.writeLong(previousIOTime);
             }
@@ -370,10 +370,10 @@ public IoStats(StreamInput in) throws IOException {
             this.totalWriteOperations = in.readLong();
             this.totalReadKilobytes = in.readLong();
             this.totalWriteKilobytes = in.readLong();
-            if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (in.getVersion().onOrAfter(Version.V_7_14_0)) {
                 this.totalIOTimeInMillis = in.readLong();
             } else {
-                this.totalIOTimeInMillis = 0;
+                this.totalIOTimeInMillis = -1;
             }
         }
 
@@ -388,7 +388,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeLong(totalWriteOperations);
             out.writeLong(totalReadKilobytes);
             out.writeLong(totalWriteKilobytes);
-            if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            if (out.getVersion().onOrAfter(Version.V_7_14_0)) {
                 out.writeLong(totalIOTimeInMillis);
             }
         }