diff --git a/.travis.yml b/.travis.yml
index 4b69742..a86625e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,2 @@
-language: python
-python:
-  - "3.6"
-install:
-  - pip install -r docs/requirements.txt
 script:
-  - sphinx-versioning build -b -B 1.5 -r 1.5 -w '^[0-9.]*$' -w master -W '^$' docs/ build/
-  - python docs/conf.py build $DEPLOY_HOST $DEPLOY_USERNAME $DEPLOY_PASSWORD $DEPLOY_REMOTEDIR
+  - /bin/true
diff --git a/core/admin/Dockerfile b/core/admin/Dockerfile
index f0209d3..bdc2bbe 100644
--- a/core/admin/Dockerfile
+++ b/core/admin/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3-alpine
+FROM python:3-alpine3.7
 
 RUN mkdir -p /app
 WORKDIR /app
diff --git a/core/dovecot/Dockerfile b/core/dovecot/Dockerfile
index 9e87f12..0bd6ecf 100644
--- a/core/dovecot/Dockerfile
+++ b/core/dovecot/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:edge
+FROM alpine:3.7
 
 RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
  && apk add --no-cache \
diff --git a/core/dovecot/sieve/report-ham.sieve b/core/dovecot/sieve/report-ham.sieve
index 8996206..1ad8abd 100644
--- a/core/dovecot/sieve/report-ham.sieve
+++ b/core/dovecot/sieve/report-ham.sieve
@@ -1,3 +1,11 @@
-require "vnd.dovecot.execute";
+require ["vnd.dovecot.execute", "copy", "imapsieve", "environment", "variables"];
+
+if environment :matches "imap.mailbox" "*" {
+  set "mailbox" "${1}";
+}
+
+if string "${mailbox}" "Trash" {
+  stop;
+}
 
 execute :pipe "mailtrain" "ham";
diff --git a/core/none/Dockerfile b/core/none/Dockerfile
index 979699d..480a615 100644
--- a/core/none/Dockerfile
+++ b/core/none/Dockerfile
@@ -1,5 +1,5 @@
 # This is an idle image to dynamically replace any component if disabled.
 
-FROM alpine
+FROM alpine:3.7
 
 CMD sleep 1000000d
diff --git a/core/postfix/Dockerfile b/core/postfix/Dockerfile
index 4dc1c89..49abfce 100644
--- a/core/postfix/Dockerfile
+++ b/core/postfix/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine
+FROM alpine:3.7
 
 RUN apk add --no-cache postfix postfix-sqlite postfix-pcre rsyslog python py-jinja2
 
diff --git a/docs/compose/setup.rst b/docs/compose/setup.rst
index cd316b0..1bb955e 100644
--- a/docs/compose/setup.rst
+++ b/docs/compose/setup.rst
@@ -90,7 +90,7 @@ setting. The configuration option must be one of the following:
 - ``none`` disables antivirus checks;
 - ``clamav`` is the default values, the popular ClamAV antivirus is enabled.
 
-Make sure that you have at least 1GB or memory for ClamAV to load its signature
+Make sure that you have at least 1GB of memory for ClamAV to load its signature
 database.
 
 Finish setting up TLS
diff --git a/docs/index.rst b/docs/index.rst
index 0920bb9..52224dc 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -25,7 +25,7 @@ Main features include:
 
 - **Standard email server**, IMAP and IMAP+, SMTP and Submission
 - **Advanced email features**, aliases, domain aliases, custom routing
-- **Web access**, multiple Webmails and adminitration interface
+- **Web access**, multiple Webmails and administration interface
 - **User features**, aliases, auto-reply, auto-forward, fetched accounts
 - **Admin features**, global admins, announcements, per-domain delegation, quotas
 - **Security**, enforced TLS, Letsencrypt!, outgoing DKIM, anti-virus scanner
diff --git a/optional/clamav/Dockerfile b/optional/clamav/Dockerfile
index 5b7b99d..eb41f84 100644
--- a/optional/clamav/Dockerfile
+++ b/optional/clamav/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:edge
+FROM alpine:3.7
 
 RUN apk add --no-cache clamav rsyslog wget clamav-libunrar
 
diff --git a/optional/radicale/Dockerfile b/optional/radicale/Dockerfile
index dce888b..6749606 100644
--- a/optional/radicale/Dockerfile
+++ b/optional/radicale/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:edge
+FROM alpine:3.7
 
 RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
  && apk add --no-cache radicale@testing py-dulwich@testing
diff --git a/services/fetchmail/Dockerfile b/services/fetchmail/Dockerfile
index a44c6e5..06444ee 100644
--- a/services/fetchmail/Dockerfile
+++ b/services/fetchmail/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:alpine
+FROM python:alpine3.7
 
 RUN apk add --no-cache fetchmail ca-certificates
 
diff --git a/services/rspamd/Dockerfile b/services/rspamd/Dockerfile
index b63d06c..b36be8c 100644
--- a/services/rspamd/Dockerfile
+++ b/services/rspamd/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:edge
+FROM alpine:3.7
 
 RUN apk add --no-cache python py-jinja2 rspamd rspamd-controller rspamd-proxy ca-certificates
 
diff --git a/webmails/roundcube/Dockerfile b/webmails/roundcube/Dockerfile
index f96b91d..7131b12 100644
--- a/webmails/roundcube/Dockerfile
+++ b/webmails/roundcube/Dockerfile
@@ -4,7 +4,7 @@ RUN apt-get update && apt-get install -y \
       libfreetype6-dev \
       libjpeg62-turbo-dev \
       libmcrypt-dev \
-      libpng12-dev \
+      libpng-dev \
  && docker-php-ext-install pdo_mysql mcrypt
 
 ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.3.3/roundcubemail-1.3.3-complete.tar.gz