diff --git a/.github/scripts/generate-version.sh b/.github/scripts/generate-version.sh
new file mode 100755
index 0000000000..d8563b7f53
--- /dev/null
+++ b/.github/scripts/generate-version.sh
@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# Validates VERSION_NAME and computes VERSION_CODE and FILE_NAME.
+#
+# Required environment variables:
+#   VERSION_NAME    e.g. "2026.2.0"
+#   VERSION_SUFFIX  e.g. "dev", "staging", "internal"
+#   RUN_ATTEMPT     github.run_attempt — must be 1 (re-runs are not allowed)
+#   RUN_NUMBER      github.run_number
+#
+# Outputs are appended to $GITHUB_ENV (or stdout if GITHUB_ENV is unset).
+
+set -euo pipefail
+
+# Re-runs are disabled because VERSION_CODE uses only run_number for its sequence slot.
+if [ "${RUN_ATTEMPT}" -ne 1 ]; then
+    echo "ERROR: Workflow re-runs are not allowed for this build; trigger a new run instead" >&2
+    exit 1
+fi
+
+# Validate VERSION_NAME format: YYYY.M.P (e.g. 2026.2.0)
+if ! echo "$VERSION_NAME" | grep -qE '^[0-9]{4}\.[0-9]{1,2}\.[0-9]{1,2}$'; then
+    echo "ERROR: VERSION_NAME '$VERSION_NAME' does not match required format YYYY.M.P" >&2
+    exit 1
+fi
+
+IFS='.' read -r VERSION_YEAR VERSION_MINOR VERSION_PATCH <<< "$VERSION_NAME"
+# Force base-10 to avoid octal misinterpretation (e.g. 08, 09)
+VERSION_YEAR=$((10#$VERSION_YEAR))
+VERSION_MINOR=$((10#$VERSION_MINOR))
+VERSION_PATCH=$((10#$VERSION_PATCH))
+
+if [ "$VERSION_YEAR" -lt 2020 ] || [ "$VERSION_YEAR" -gt 2099 ]; then
+    echo "ERROR: Version year $VERSION_YEAR is out of supported range (2020-2099)" >&2
+    exit 1
+fi
+
+if [ "$VERSION_MINOR" -gt 99 ] || [ "$VERSION_PATCH" -gt 99 ]; then
+    echo "ERROR: Minor ($VERSION_MINOR) and patch ($VERSION_PATCH) must each be 0-99" >&2
+    exit 1
+fi
+
+VERSION_CODE_CALCULATED=$(( (VERSION_YEAR - 2000) * 10000000 + VERSION_MINOR * 100000 + VERSION_PATCH * 1000 + RUN_NUMBER ))
+
+if [ "$VERSION_CODE_CALCULATED" -gt 2100000000 ]; then
+    echo "ERROR: VERSION_CODE $VERSION_CODE_CALCULATED exceeds Android max 2100000000" >&2
+    exit 1
+fi
+
+DEST="${GITHUB_ENV:-/dev/stdout}"
+echo "VERSION_CODE=$VERSION_CODE_CALCULATED" >> "$DEST"
+echo "VERSION_BUILD=${RUN_NUMBER}.${RUN_ATTEMPT}" >> "$DEST"
+echo "FILE_NAME=${VERSION_NAME}+${VERSION_SUFFIX}.${RUN_NUMBER}" >> "$DEST"
diff --git a/.github/scripts/test-generate-version.sh b/.github/scripts/test-generate-version.sh
new file mode 100755
index 0000000000..dde14864cd
--- /dev/null
+++ b/.github/scripts/test-generate-version.sh
@@ -0,0 +1,253 @@
+#!/usr/bin/env bash
+# Tests for generate-version.sh
+#
+# Run from any directory: bash .github/scripts/test-generate-version.sh
+# Exit code 0 = all tests passed, non-zero = one or more failures.
+
+set -uo pipefail
+
+SCRIPT="$(cd "$(dirname "$0")" && pwd)/generate-version.sh"
+PASS=0
+FAIL=0
+
+# ---------------------------------------------------------------------------
+# Test runner helpers
+# ---------------------------------------------------------------------------
+
+_run() {
+    # _run VERSION_NAME RUN_ATTEMPT RUN_NUMBER VERSION_SUFFIX
+    local env_file
+    env_file="$(mktemp "${TMPDIR:-/tmp}/gen_version_test.XXXXXX")"
+    _OUTPUT=$(VERSION_NAME="$1" RUN_ATTEMPT="$2" RUN_NUMBER="$3" VERSION_SUFFIX="$4" \
+        GITHUB_ENV="$env_file" bash "$SCRIPT" 2>&1)
+    _EXIT=$?
+    _ENV_CONTENT="$(cat "$env_file" 2>/dev/null || true)"
+    rm -f "$env_file"
+}
+
+_get_env() {
+    # Extract a key's value written to GITHUB_ENV
+    echo "$_ENV_CONTENT" | grep "^${1}=" | cut -d= -f2-
+}
+
+assert_success() {
+    # assert_success LABEL EXPECTED_CODE EXPECTED_BUILD EXPECTED_FILE VERSION_NAME RUN_ATTEMPT RUN_NUMBER VERSION_SUFFIX
+    local label="$1" expected_code="$2" expected_build="$3" expected_file="$4"
+    shift 4
+    _run "$@"
+
+    if [ "$_EXIT" -ne 0 ]; then
+        echo "FAIL [$label]: expected success but got exit $_EXIT — $_OUTPUT"
+        FAIL=$(( FAIL + 1 ))
+        return
+    fi
+
+    local actual_code actual_build actual_file
+    actual_code="$(_get_env VERSION_CODE)"
+    actual_build="$(_get_env VERSION_BUILD)"
+    actual_file="$(_get_env FILE_NAME)"
+
+    local ok=1
+    if [ "$actual_code" != "$expected_code" ]; then
+        echo "FAIL [$label]: VERSION_CODE expected=$expected_code actual=$actual_code"
+        ok=0
+    fi
+    if [ "$actual_build" != "$expected_build" ]; then
+        echo "FAIL [$label]: VERSION_BUILD expected=$expected_build actual=$actual_build"
+        ok=0
+    fi
+    if [ "$actual_file" != "$expected_file" ]; then
+        echo "FAIL [$label]: FILE_NAME expected=$expected_file actual=$actual_file"
+        ok=0
+    fi
+
+    if [ "$ok" -eq 1 ]; then
+        echo "PASS [$label]"
+        PASS=$(( PASS + 1 ))
+    else
+        FAIL=$(( FAIL + 1 ))
+    fi
+}
+
+assert_failure() {
+    # assert_failure LABEL EXPECTED_ERROR_SUBSTRING VERSION_NAME RUN_ATTEMPT RUN_NUMBER VERSION_SUFFIX
+    local label="$1" expected_msg="$2"
+    shift 2
+    _run "$@"
+
+    if [ "$_EXIT" -eq 0 ]; then
+        echo "FAIL [$label]: expected failure but script succeeded (output: $_OUTPUT)"
+        FAIL=$(( FAIL + 1 ))
+        return
+    fi
+
+    if ! echo "$_OUTPUT" | grep -qF "$expected_msg"; then
+        echo "FAIL [$label]: expected error containing '$expected_msg', got: $_OUTPUT"
+        FAIL=$(( FAIL + 1 ))
+        return
+    fi
+
+    echo "PASS [$label]"
+    PASS=$(( PASS + 1 ))
+}
+
+# ---------------------------------------------------------------------------
+# Valid cases — formula: (year-2000)*10_000_000 + minor*100_000 + patch*1_000 + run_number
+# ---------------------------------------------------------------------------
+
+# Standard release: 2026.2.0, run 345
+# = 26*10_000_000 + 2*100_000 + 0 + 345 = 260_200_345
+assert_success "standard release" \
+    "260200345" "345.1" "2026.2.0+dev.345" \
+    "2026.2.0" 1 345 "dev"
+
+# With non-zero patch: 2026.2.1, run 345
+# = 260_000_000 + 200_000 + 1_000 + 345 = 260_201_345
+assert_success "non-zero patch" \
+    "260201345" "345.1" "2026.2.1+staging.345" \
+    "2026.2.1" 1 345 "staging"
+
+# Octal edge case — leading zeros in month/patch (08, 09 must not be interpreted as octal)
+# 2026.08.09, run 1 → (26)*10M + 8*100K + 9*1K + 1 = 260_809_001
+assert_success "octal edge case 08.09" \
+    "260809001" "1.1" "2026.08.09+dev.1" \
+    "2026.08.09" 1 1 "dev"
+
+# Another octal edge: 2026.09.08, run 1 → 260_000_000 + 900_000 + 8_000 + 1 = 260_908_001
+assert_success "octal edge case 09.08" \
+    "260908001" "1.1" "2026.09.08+dev.1" \
+    "2026.09.08" 1 1 "dev"
+
+# Double-digit minor: 2026.21.0, run 50 → 260_000_000 + 2_100_000 + 0 + 50 = 262_100_050
+assert_success "double-digit minor" \
+    "262100050" "50.1" "2026.21.0+internal.50" \
+    "2026.21.0" 1 50 "internal"
+
+# Double-digit patch: 2026.2.10, run 50 → 260_000_000 + 200_000 + 10_000 + 50 = 260_210_050
+assert_success "double-digit patch" \
+    "260210050" "50.1" "2026.2.10+dev.50" \
+    "2026.2.10" 1 50 "dev"
+
+# Double-digit minor and patch: 2026.21.10, run 50 → 260_000_000 + 2_100_000 + 10_000 + 50 = 262_110_050
+assert_success "double-digit minor and patch" \
+    "262110050" "50.1" "2026.21.10+dev.50" \
+    "2026.21.10" 1 50 "dev"
+
+# Minimum valid year: 2020.1.0, run 1 → 20*10M + 100_000 + 0 + 1 = 200_100_001
+assert_success "minimum year boundary" \
+    "200100001" "1.1" "2020.1.0+dev.1" \
+    "2020.1.0" 1 1 "dev"
+
+# Maximum valid values: 2099.99.99, run 999 → 99*10M + 9_900_000 + 99_000 + 999 = 999_999_999
+assert_success "maximum valid values" \
+    "999999999" "999.1" "2099.99.99+dev.999" \
+    "2099.99.99" 1 999 "dev"
+
+# run_number 1000 — no longer wraps, adds directly
+# 2026.2.0, run 1000 → 260_200_000 + 1_000 = 260_201_000
+assert_success "run_number 1000 does not wrap" \
+    "260201000" "1000.1" "2026.2.0+dev.1000" \
+    "2026.2.0" 1 1000 "dev"
+
+# run_number 2000 — adds directly
+# 2026.2.0, run 2000 → 260_200_000 + 2_000 = 260_202_000
+assert_success "run_number 2000 does not wrap" \
+    "260202000" "2000.1" "2026.2.0+dev.2000" \
+    "2026.2.0" 1 2000 "dev"
+
+# Large run_number: 5001 → adds directly
+# 2026.2.0, run 5001 → 260_200_000 + 5_001 = 260_205_001
+assert_success "large run_number" \
+    "260205001" "5001.1" "2026.2.0+dev.5001" \
+    "2026.2.0" 1 5001 "dev"
+
+# run_number at 999
+assert_success "run_number at 999" \
+    "260200999" "999.1" "2026.2.0+dev.999" \
+    "2026.2.0" 1 999 "dev"
+
+# Patch at boundary 99: 2026.1.99, run 1 → 260_000_000 + 100_000 + 99_000 + 1 = 260_199_001
+assert_success "patch boundary 99" \
+    "260199001" "1.1" "2026.1.99+dev.1" \
+    "2026.1.99" 1 1 "dev"
+
+# Minor at boundary 99: 2026.99.0, run 1 → 260_000_000 + 9_900_000 + 0 + 1 = 269_900_001
+assert_success "minor boundary 99" \
+    "269900001" "1.1" "2026.99.0+dev.1" \
+    "2026.99.0" 1 1 "dev"
+
+# All components at single digit minimums: 2020.0.0, run 1 → 200_000_001
+assert_success "minor and patch at 0" \
+    "200000001" "1.1" "2020.0.0+dev.1" \
+    "2020.0.0" 1 1 "dev"
+
+# ---------------------------------------------------------------------------
+# Invalid cases — re-run detection
+# ---------------------------------------------------------------------------
+
+assert_failure "re-run attempt=2" "re-runs are not allowed" \
+    "2026.2.0" 2 345 "dev"
+
+assert_failure "re-run attempt=3" "re-runs are not allowed" \
+    "2026.2.0" 3 1 "dev"
+
+# ---------------------------------------------------------------------------
+# Invalid cases — VERSION_NAME format
+# ---------------------------------------------------------------------------
+
+assert_failure "missing patch component" "does not match required format" \
+    "2026.2" 1 1 "dev"
+
+assert_failure "2-digit year" "does not match required format" \
+    "26.2.0" 1 1 "dev"
+
+assert_failure "3-digit year" "does not match required format" \
+    "202.2.0" 1 1 "dev"
+
+assert_failure "extra 4th component" "does not match required format" \
+    "2026.2.0.1" 1 1 "dev"
+
+assert_failure "alphabetic minor" "does not match required format" \
+    "2026.a.0" 1 1 "dev"
+
+assert_failure "alphabetic patch" "does not match required format" \
+    "2026.2.b" 1 1 "dev"
+
+assert_failure "empty version name" "does not match required format" \
+    "" 1 1 "dev"
+
+assert_failure "only dots" "does not match required format" \
+    "..." 1 1 "dev"
+
+# 3-digit minor (100) is rejected by the regex before the range check
+assert_failure "3-digit minor 100 rejected by format" "does not match required format" \
+    "2026.100.0" 1 1 "dev"
+
+# 3-digit patch (100) is rejected by the regex before the range check
+assert_failure "3-digit patch 100 rejected by format" "does not match required format" \
+    "2026.1.100" 1 1 "dev"
+
+# ---------------------------------------------------------------------------
+# Invalid cases — year out of range
+# ---------------------------------------------------------------------------
+
+assert_failure "year below minimum (2019)" "out of supported range" \
+    "2019.1.0" 1 1 "dev"
+
+assert_failure "year at 2000 (below minimum)" "out of supported range" \
+    "2000.1.0" 1 1 "dev"
+
+assert_failure "year above maximum (2100)" "out of supported range" \
+    "2100.1.0" 1 1 "dev"
+
+# ---------------------------------------------------------------------------
+# Summary
+# ---------------------------------------------------------------------------
+
+TOTAL=$(( PASS + FAIL ))
+echo ""
+echo "Results: $PASS/$TOTAL passed"
+
+if [ "$FAIL" -gt 0 ]; then
+    exit 1
+fi
diff --git a/.github/workflows/reusable-build-apk.yml b/.github/workflows/reusable-build-apk.yml
index b920d9c235..aa06c6a01e 100644
--- a/.github/workflows/reusable-build-apk.yml
+++ b/.github/workflows/reusable-build-apk.yml
@@ -30,18 +30,12 @@ jobs:
         environment: ${{ inputs.build-environment }}
 
         env:
-            # VERSION_CODE: Unique version code using the sum of the current timestamp and run number.
+            # VERSION_CODE formula: (year-2000)*10_000_000 + minor*100_000 + patch*1_000 + run_number
+            # Re-runs are disabled: github.run_attempt must be 1.
             VERSION_CODE: "set in lower step"
-            # VERSION_NAME: Version name derived from the GitHub ref name after the final /.
             VERSION_NAME: ${{ inputs.version-name }}
-            # VERSION_SUFFIX: The build environment (e.g., dev, staging, internal).
             VERSION_SUFFIX: ${{ inputs.build-environment }}
-            # VERSION_BUILD: A unique build identifier combining the run number and attempt.
-            VERSION_BUILD: ${{ github.run_number }}.${{ github.run_attempt }}
-            # The final output file name.
             FILE_NAME: "set in lower step"
-            # The base floor version code. Please check the README for more information.
-            BASE_VERSION_CODE: 10000000
 
         steps:
             -   name: Checkout
@@ -53,26 +47,11 @@ jobs:
                     java-version: 21
                     distribution: 'temurin'
 
-            -   name: Check workflow validity
-                if: ${{ github.run_attempt > 99 }}
-                run: |
-                    echo "Run attempts exceeded 99. Please start a new workflow."
-                    exit 1
-
-            -   name: Check base version code
-                run: |
-                    if [ $(( ${{ github.run_number }} * 100 )) -ge $BASE_VERSION_CODE ]; then
-                      echo "Github workflows now exceeds the base version code..."
-                      echo "BASE_VERSION_CODE=0" >> $GITHUB_ENV
-                    fi
-
-            -   name: Compute version variables
-                run: |
-                    echo "VERSION_CODE=$(($BASE_VERSION_CODE + ${{ github.run_number }} * 100 + ${{ github.run_attempt }}))" >> $GITHUB_ENV
-
-            -   name: Compute file name
-                run: |
-                    echo "FILE_NAME=${{ env.VERSION_NAME }}+${{ env.VERSION_SUFFIX }}.${{ env.VERSION_BUILD }}" >> $GITHUB_ENV
+            -   name: Validate version name and compute version code
+                env:
+                    RUN_ATTEMPT: ${{ github.run_attempt }}
+                    RUN_NUMBER: ${{ github.run_number }}
+                run: bash .github/scripts/generate-version.sh
 
             -   name: Set up build files
                 uses: ./.github/actions/setup-gradle-build-files
diff --git a/.github/workflows/test-version-generation.yml b/.github/workflows/test-version-generation.yml
new file mode 100644
index 0000000000..da1f8db572
--- /dev/null
+++ b/.github/workflows/test-version-generation.yml
@@ -0,0 +1,18 @@
+name: Test version generation
+
+on:
+    workflow_dispatch:
+    push:
+        paths:
+            - '.github/scripts/generate-version.sh'
+            - '.github/scripts/test-generate-version.sh'
+
+jobs:
+    test-version-generation:
+        runs-on: ubuntu-latest
+        steps:
+            -   name: Checkout
+                uses: actions/checkout@v4
+
+            -   name: Run version generation tests
+                run: bash .github/scripts/test-generate-version.sh