The version now comes from the git tag, so a build can't disagree with its release

Builds after a tag name themselves after it plus the commits since, and the version code is
worked out from the numbers instead of set by hand.

gearslip/src/main/java/app/seb3thehacker/gearslip/Changelog.kt

@@ -4,6 +4,10 @@ package app.seb3thehacker.gearslip
  * What changed in each release, newest first, shown on the car screen after an update (and on
  * the phone). Only the changes a driver would notice. Plain words, short lines: this is read in
  * a parked car.
+ *
+ * After 0.3.40, the version code is the one the build works out from the tag (see gitVersion in
+ * build.gradle.kts): ((major*100 + minor)*100 + patch)*10 + stage, so 0.4.0-beta is 4002. Older
+ * entries keep the hand-set codes they shipped with, which are all lower.
  */
 object Changelog {
 

gearslip/src/main/java/app/seb3thehacker/gearslip/update/UpdateChecker.kt

@@ -578,12 +578,14 @@ object UpdateChecker {
     /**
      * "0.2.00-alpha" beats "0.1.10-alpha": the numbers before the dash compare one by one. With the
      * same numbers, a plain release beats a beta, and a beta beats an alpha, so "0.3.0" reaches
-     * someone on "0.3.0-beta".
+     * someone on "0.3.0-beta". Anything after a "+" only says which commit a test build came from,
+     * so "0.3.0-beta+4.ba4374e" counts the same as "0.3.0-beta".
      */
     internal fun isNewer(candidate: String, installed: String): Boolean {
-        fun parts(v: String) = v.removePrefix("v").substringBefore('-').split('.').map { it.toIntOrNull() ?: 0 }
+        fun core(v: String) = v.removePrefix("v").substringBefore('+')
+        fun parts(v: String) = core(v).substringBefore('-').split('.').map { it.toIntOrNull() ?: 0 }
         fun stage(v: String): Int {
-            val tag = v.substringAfter('-', "").lowercase()
+            val tag = core(v).substringAfter('-', "").lowercase()
             return when {
                 tag.isEmpty() -> 3
                 "beta" in tag -> 2