diff --git a/briar-core/build.gradle b/briar-core/build.gradle
index c9222bdd8..14bc3aa16 100644
--- a/briar-core/build.gradle
+++ b/briar-core/build.gradle
@@ -12,7 +12,8 @@ dependencies {
 	implementation project(path: ':briar-api', configuration: 'default')
 	implementation 'com.rometools:rome:1.12.1'
 	implementation 'org.jdom:jdom2:2.0.6'
-	implementation 'com.squareup.okhttp3:okhttp:3.14.4'
+	// okhttp 3.12.x is supported until end of 2020, newer versions need minSdk 21
+	implementation 'com.squareup.okhttp3:okhttp:3.12.6'
 	implementation 'org.jsoup:jsoup:1.11.3'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'
diff --git a/briar-core/witness.gradle b/briar-core/witness.gradle
index a001799c4..603dd3432 100644
--- a/briar-core/witness.gradle
+++ b/briar-core/witness.gradle
@@ -15,8 +15,8 @@ dependencyVerification {
         'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:2994a7eb78f2710bd3d3bfb639b2c94e219cedac0d4d084d516e78c16dddecf6',
         'com.rometools:rome-utils:1.12.1:rome-utils-1.12.1.jar:d65ce5f0926ee80e1ed19b176428846098000fc4db09360a1b4dd3a1a36ed477',
         'com.rometools:rome:1.12.1:rome-1.12.1.jar:13414d70a6c185e1374588321861c6e9eb7928eee502d032094ef3ca0fd921ae',
-        'com.squareup.okhttp3:okhttp:3.14.4:okhttp-3.14.4.jar:58ccb3754f15cc42df8f1687b3ba86330ed97c7e52e5c3e83fe1131b80ce3e0f',
-        'com.squareup.okio:okio:1.17.2:okio-1.17.2.jar:f80ce42d2ffac47ad4c47e1d6f980d604d247ceb1a886705cf4581ab0c9fe2b8',
+        'com.squareup.okhttp3:okhttp:3.12.6:okhttp-3.12.6.jar:ab45b9be99d9f070662b722cece5bdc2a0449fd34b9d5e51cdcd34663ae7b610',
+        'com.squareup.okio:okio:1.15.0:okio-1.15.0.jar:693fa319a7e8843300602b204023b7674f106ebcb577f2dd5807212b66118bd2',
         'com.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',
         'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',