diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b5dfeb64..81376915 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -13,7 +13,7 @@ jobs:
       - name: checkout
         uses: actions/checkout@v2
         with:
-          ref: "master"
+          ref: ${{ github.event.release.target_commitish }}
           token: ${{secrets.SERVICE_PERSONAL_ACCESS_TOKEN}}
           submodules: recursive
 
@@ -40,7 +40,7 @@ jobs:
       - name: checkout
         uses: actions/checkout@v2
         with:
-          ref: "master"
+          ref: ${{ github.event.release.target_commitish }}
           token: ${{secrets.SERVICE_PERSONAL_ACCESS_TOKEN}}
           submodules: recursive
 
@@ -83,7 +83,7 @@ jobs:
         id: commit
         uses: stefanzweifel/git-auto-commit-action@v4
         with:
-          branch: master
+          branch: ${{ github.event.release.target_commitish }}
           commit_message: "Automatic changelog update"
           file_pattern: "gradle.properties CHANGELOG.md"
 
@@ -96,7 +96,7 @@ jobs:
       - name: checkout
         uses: actions/checkout@v2
         with:
-          ref: "master"
+          ref: ${{ github.event.release.target_commitish }}
           token: ${{secrets.SERVICE_PERSONAL_ACCESS_TOKEN}}
           submodules: recursive
 
diff --git a/build.gradle b/build.gradle
index 4450ac64..7d4cd599 100644
--- a/build.gradle
+++ b/build.gradle
@@ -10,14 +10,14 @@ buildscript {
 
     dependencies {
         classpath 'com.android.tools.build:gradle:4.2.2'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.21"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.32"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
 }
 
 plugins {
-    id 'org.jetbrains.kotlin.plugin.serialization' version "1.5.21"
+    id 'org.jetbrains.kotlin.plugin.serialization' version "1.4.32"
     id 'org.jetbrains.dokka' version '1.5.0'
     id "io.github.gradle-nexus.publish-plugin" version "1.1.0"
 }
diff --git a/cardscan-demo/build.gradle b/cardscan-demo/build.gradle
index 04796665..3b6766e0 100644
--- a/cardscan-demo/build.gradle
+++ b/cardscan-demo/build.gradle
@@ -52,11 +52,11 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
diff --git a/cardscan-ui/build.gradle b/cardscan-ui/build.gradle
index 78a2a2f1..091f1abd 100644
--- a/cardscan-ui/build.gradle
+++ b/cardscan-ui/build.gradle
@@ -54,14 +54,14 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 apply from: 'deploy.gradle'
diff --git a/scan-camera/build.gradle b/scan-camera/build.gradle
index 70408fc1..6b197d51 100644
--- a/scan-camera/build.gradle
+++ b/scan-camera/build.gradle
@@ -47,14 +47,14 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 apply from: 'deploy.gradle'
diff --git a/scan-camera2/build.gradle b/scan-camera2/build.gradle
index 7e7e9ed8..44af3d86 100644
--- a/scan-camera2/build.gradle
+++ b/scan-camera2/build.gradle
@@ -47,13 +47,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 apply from: 'deploy.gradle'
diff --git a/scan-camerax/build.gradle b/scan-camerax/build.gradle
index 82a4ffaf..81dcbef8 100644
--- a/scan-camerax/build.gradle
+++ b/scan-camerax/build.gradle
@@ -51,13 +51,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 apply from: 'deploy.gradle'
diff --git a/scan-framework/build.gradle b/scan-framework/build.gradle
index 4294a99a..268e6955 100644
--- a/scan-framework/build.gradle
+++ b/scan-framework/build.gradle
@@ -58,14 +58,14 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
diff --git a/scan-framework/src/main/java/com/getbouncer/scan/framework/util/Device.kt b/scan-framework/src/main/java/com/getbouncer/scan/framework/util/Device.kt
index 78b41d42..671cd51d 100644
--- a/scan-framework/src/main/java/com/getbouncer/scan/framework/util/Device.kt
+++ b/scan-framework/src/main/java/com/getbouncer/scan/framework/util/Device.kt
@@ -110,8 +110,11 @@ fun getPlatform() = "android"
  * from https://stackoverflow.com/a/27836910/947883
  */
 fun getDeviceName(): String {
-    val manufacturer = Build.MANUFACTURER?.lowercase() ?: ""
-    val model = Build.MODEL?.lowercase() ?: ""
+    // TODO: change this back once we can support newer kotlin versions
+//    val manufacturer = Build.MANUFACTURER?.lowercase() ?: ""
+//    val model = Build.MODEL?.lowercase() ?: ""
+    val manufacturer = Build.MANUFACTURER?.toLowerCase(Locale.ROOT) ?: ""
+    val model = Build.MODEL?.toLowerCase(Locale.ROOT) ?: ""
     return if (model.startsWith(manufacturer)) {
         model
     } else {
diff --git a/scan-payment-full/build.gradle b/scan-payment-full/build.gradle
index 2c22973a..107017cc 100644
--- a/scan-payment-full/build.gradle
+++ b/scan-payment-full/build.gradle
@@ -58,13 +58,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
diff --git a/scan-payment-minimal/build.gradle b/scan-payment-minimal/build.gradle
index 12afb77a..8ba0454b 100644
--- a/scan-payment-minimal/build.gradle
+++ b/scan-payment-minimal/build.gradle
@@ -54,13 +54,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
diff --git a/scan-payment/build.gradle b/scan-payment/build.gradle
index c4a26d87..dc39eb47 100644
--- a/scan-payment/build.gradle
+++ b/scan-payment/build.gradle
@@ -53,13 +53,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
     androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.4.3"
 }
 
diff --git a/scan-payment/src/main/java/com/getbouncer/scan/payment/ml/AlphabetDetect.kt b/scan-payment/src/main/java/com/getbouncer/scan/payment/ml/AlphabetDetect.kt
index e899acec..7209dac8 100644
--- a/scan-payment/src/main/java/com/getbouncer/scan/payment/ml/AlphabetDetect.kt
+++ b/scan-payment/src/main/java/com/getbouncer/scan/payment/ml/AlphabetDetect.kt
@@ -37,7 +37,9 @@ class AlphabetDetect private constructor(interpreter: Interpreter) :
         val prediction = mlOutput[0]
         val index = prediction.indexOfMax()
         val character = if (index != null && index > 0) {
-            ('A'.code - 1 + index).toChar()
+            // TODO: change this back once we support newer gradle versions
+//            ('A'.code - 1 + index).toChar()
+            ('A'.toInt() - 1 + index).toChar()
         } else {
             ' '
         }
diff --git a/scan-ui/build.gradle b/scan-ui/build.gradle
index c1183f3d..3c1a6a85 100644
--- a/scan-ui/build.gradle
+++ b/scan-ui/build.gradle
@@ -49,13 +49,13 @@ dependencies {
     testImplementation "androidx.test:core:1.4.0"
     testImplementation "androidx.test:runner:1.4.0"
     testImplementation "junit:junit:4.13.2"
-    testImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    testImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 dependencies {
     androidTestImplementation "androidx.test.ext:junit:1.1.3"
     androidTestImplementation "androidx.test.espresso:espresso-core:3.4.0"
-    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.5.21"
+    androidTestImplementation "org.jetbrains.kotlin:kotlin-test:1.4.32"
 }
 
 apply from: 'deploy.gradle'