diff --git a/Dockerfile b/Dockerfile
index ac0ed53..e845de9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM golang:1.13-stretch as builder
 # Install pebble
 ARG PEBBLE_REMOTE=
-ARG PEBBLE_CHECKOUT="7e026bbfe639ff65dbafacd1b4259a660a8c513f"
+ARG PEBBLE_CHECKOUT="746c32eb265131059a2a340388a4bc7c37405cfc"
 ENV GOPATH=/go
 RUN go get -v -u github.com/letsencrypt/pebble/... && \
     cd /go/src/github.com/letsencrypt/pebble && \
diff --git a/requirements.txt b/requirements.txt
index 8dbc7ed..430f290 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,15 @@
-Flask==1.0.2
-Werkzeug==0.14.1
-pyOpenSSL==18.0.0
-dnslib==0.9.7
+# Requirements
+Flask==1.1.1
+pyOpenSSL==19.0.0
+dnslib==0.9.10
+
+# Implicit requirements to make Python part reproducable
+Jinja2==2.10.3
+MarkupSafe==1.1.1
+Werkzeug==0.16.0
+cffi==1.13.2
+click==7.0
+cryptography==2.8
+itsdangerous==1.1.0
+pycparser==2.19
+six==1.12.0