diff --git a/.gitignore b/.gitignore
index 26422e13..abc69ff0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,3 @@ hook.sh
 certs/*
 archive/*
 accounts/*
-.acme-challenges/*
diff --git a/CHANGELOG b/CHANGELOG
index e6cd3433..20769e11 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -6,13 +6,17 @@ This file contains a log of major changes in letsencrypt.sh
 - Config is now named `config` instead of `config.sh`!
 - Location of domains.txt is now configurable via DOMAINS_TXT config variable
 - Location of certs directory is now configurable via CERTDIR config variable
-- signcsr command now also outputs chain certificate
+- signcsr command now also outputs chain certificate if --full-chain/-fc is set
 - Location of account-key(s) changed
+- Default WELLKNOWN location is now `/var/www/letsencrypt`
+- New version of Let's Encrypt Subscriber Agreement
 
 ## Added
 - Added option to add CSR-flag indicating OCSP stapling to be mandatory
 - Initial support for configuration on per-certificate base
 - Support for per-CA account keys and custom config for output cert directory, license, etc.
+- Added option to select IP version of name to address resolution
+- Added option to run letsencrypt.sh without locks
 
 ## Fixed
 - letsencrypt.sh no longer stores account keys from invalid registrations
diff --git a/README.md b/README.md
index 65632430..81bbd10c 100644
--- a/README.md
+++ b/README.md
@@ -41,8 +41,13 @@ Commands:
  --env (-e)                       Output configuration variables for use in other scripts
 
 Parameters:
+ --full-chain (-fc)               Print full chain when using --signcsr
+ --ipv4 (-4)                      Resolve names to IPv4 addresses only
+ --ipv6 (-6)                      Resolve names to IPv6 addresses only
  --domain (-d) domain.tld         Use specified domain name(s) instead of domains.txt entry (one certificate!)
+ --keep-going (-g)                Keep going after encountering an error while creating/renewing multiple certificates in cron mode
  --force (-x)                     Force renew of certificate even if it is longer valid than value in RENEW_DAYS
+ --no-lock (-n)                   Don't use lockfile (potentially dangerous!)
  --ocsp                           Sets option in CSR indicating OCSP stapling to be mandatory
  --privkey (-p) path/to/key.pem   Use specified private key instead of account key (useful for revocation)
  --config (-f) path/to/config     Use specified config file
diff --git a/docs/ecc.md b/docs/ecc.md
index bbe99166..87d52ba4 100644
--- a/docs/ecc.md
+++ b/docs/ecc.md
@@ -1,5 +1,4 @@
 ### Elliptic Curve Cryptography (ECC)
 
 This script also supports certificates with Elliptic Curve public keys!
-Be aware that at the moment this is not available on the production servers from letsencrypt.
-Please read https://community.letsencrypt.org/t/ecdsa-testing-on-staging/8809/ for the current state of ECC support.
+Simply set the `KEY_ALGO` variable in one of the config files.
diff --git a/docs/examples/config b/docs/examples/config
index 298eb04e..a836a4e2 100644
--- a/docs/examples/config
+++ b/docs/examples/config
@@ -10,11 +10,16 @@
 # Default values of this config are in comments        #
 ########################################################
 
+# Resolve names to addresses of IP version only. (curl)
+# supported values: 4, 6
+# default: <unset>
+#IP_VERSION=
+
 # Path to certificate authority (default: https://acme-v01.api.letsencrypt.org/directory)
 #CA="https://acme-v01.api.letsencrypt.org/directory"
 
-# Path to license agreement (default: https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf)
-#LICENSE="https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf"
+# Path to license agreement (default: https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf)
+#LICENSE="https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf"
 
 # Which challenge should be used? Currently http-01 and dns-01 are supported
 #CHALLENGETYPE="http-01"
@@ -37,8 +42,8 @@
 # Directory for account keys and registration information
 #ACCOUNTDIR="${BASEDIR}/accounts"
 
-# Output directory for challenge-tokens to be served by webserver or deployed in HOOK (default: $BASEDIR/.acme-challenges)
-#WELLKNOWN="${BASEDIR}/.acme-challenges"
+# Output directory for challenge-tokens to be served by webserver or deployed in HOOK (default: /var/www/letsencrypt)
+#WELLKNOWN="/var/www/letsencrypt"
 
 # Default keysize for private keys (default: 4096)
 #KEYSIZE="4096"
diff --git a/docs/staging.md b/docs/staging.md
index ec18445b..297db580 100644
--- a/docs/staging.md
+++ b/docs/staging.md
@@ -1,6 +1,6 @@
 # Staging
 
-Let’s Encrypt has stringent rate limits in place during the public beta period.
+Let’s Encrypt has stringent rate limits in place.
 
 If you start testing using the production endpoint (which is the default),
 you will quickly hit these limits and find yourself locked out.
@@ -10,6 +10,3 @@ To avoid this, please set the CA property to the Let’s Encrypt staging server
 ```bash
 CA="https://acme-staging.api.letsencrypt.org/directory"
 ```
-
-Please keep in mind that at the time of writing this letsencrypt.sh doesn't have support for registration management,
-so if you change CA you'll have to move your `private_key.pem` (and, if you care, `private_key.json`) out of the way.
diff --git a/letsencrypt.sh b/letsencrypt.sh
index 4efa5705..787c31f5 100755
--- a/letsencrypt.sh
+++ b/letsencrypt.sh
@@ -58,6 +58,7 @@ store_configvars() {
   __HOOK_CHAIN="${HOOK_CHAIN}"
   __OPENSSL_CNF="${OPENSSL_CNF}"
   __RENEW_DAYS="${RENEW_DAYS}"
+  __IP_VERSION="${IP_VERSION}"
 }
 
 reset_configvars() {
@@ -71,6 +72,7 @@ reset_configvars() {
   HOOK_CHAIN="${__HOOK_CHAIN}"
   OPENSSL_CNF="${__OPENSSL_CNF}"
   RENEW_DAYS="${__RENEW_DAYS}"
+  IP_VERSION="${__IP_VERSION}"
 }
 
 # verify configuration values
@@ -83,6 +85,9 @@ verify_config() {
     _exiterr "WELLKNOWN directory doesn't exist, please create ${WELLKNOWN} and set appropriate permissions."
   fi
   [[ "${KEY_ALGO}" =~ ^(rsa|prime256v1|secp384r1)$ ]] || _exiterr "Unknown public key algorithm ${KEY_ALGO}... can not continue."
+  if [[ -n "${IP_VERSION}" ]]; then
+    [[ "${IP_VERSION}" = "4" || "${IP_VERSION}" = "6" ]] || _exiterr "Unknown IP version ${IP_VERSION}... can not continue."
+  fi
 }
 
 # Setup default config values, search for and load configuration files
@@ -100,11 +105,12 @@ load_config() {
 
   # Default values
   CA="https://acme-v01.api.letsencrypt.org/directory"
-  LICENSE="https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf"
+  LICENSE="https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf"
   CERTDIR=
   ACCOUNTDIR=
   CHALLENGETYPE="http-01"
   CONFIG_D=
+  DOMAINS_D=
   DOMAINS_TXT=
   HOOK=
   HOOK_CHAIN="no"
@@ -117,6 +123,7 @@ load_config() {
   CONTACT_EMAIL=
   LOCKFILE=
   OCSP_MUST_STAPLE="no"
+  IP_VERSION=
 
   if [[ -z "${CONFIG:-}" ]]; then
     echo "#" >&2
@@ -174,14 +181,16 @@ load_config() {
 
   [[ -z "${CERTDIR}" ]] && CERTDIR="${BASEDIR}/certs"
   [[ -z "${DOMAINS_TXT}" ]] && DOMAINS_TXT="${BASEDIR}/domains.txt"
-  [[ -z "${WELLKNOWN}" ]] && WELLKNOWN="${BASEDIR}/.acme-challenges"
+  [[ -z "${WELLKNOWN}" ]] && WELLKNOWN="/var/www/letsencrypt"
   [[ -z "${LOCKFILE}" ]] && LOCKFILE="${BASEDIR}/lock"
+  [[ -n "${PARAM_NO_LOCK:-}" ]] && LOCKFILE=""
 
   [[ -n "${PARAM_HOOK:-}" ]] && HOOK="${PARAM_HOOK}"
   [[ -n "${PARAM_CERTDIR:-}" ]] && CERTDIR="${PARAM_CERTDIR}"
   [[ -n "${PARAM_CHALLENGETYPE:-}" ]] && CHALLENGETYPE="${PARAM_CHALLENGETYPE}"
   [[ -n "${PARAM_KEY_ALGO:-}" ]] && KEY_ALGO="${PARAM_KEY_ALGO}"
   [[ -n "${PARAM_OCSP_MUST_STAPLE:-}" ]] && OCSP_MUST_STAPLE="${PARAM_OCSP_MUST_STAPLE}"
+  [[ -n "${PARAM_IP_VERSION:-}" ]] && IP_VERSION="${PARAM_IP_VERSION}"
 
   verify_config
   store_configvars
@@ -192,11 +201,13 @@ init_system() {
   load_config
 
   # Lockfile handling (prevents concurrent access)
-  LOCKDIR="$(dirname "${LOCKFILE}")"
-  [[ -w "${LOCKDIR}" ]] || _exiterr "Directory ${LOCKDIR} for LOCKFILE ${LOCKFILE} is not writable, aborting."
-  ( set -C; date > "${LOCKFILE}" ) 2>/dev/null || _exiterr "Lock file '${LOCKFILE}' present, aborting."
-  remove_lock() { rm -f "${LOCKFILE}"; }
-  trap 'remove_lock' EXIT
+  if [[ -n "${LOCKFILE}" ]]; then
+    LOCKDIR="$(dirname "${LOCKFILE}")"
+    [[ -w "${LOCKDIR}" ]] || _exiterr "Directory ${LOCKDIR} for LOCKFILE ${LOCKFILE} is not writable, aborting."
+    ( set -C; date > "${LOCKFILE}" ) 2>/dev/null || _exiterr "Lock file '${LOCKFILE}' present, aborting."
+    remove_lock() { rm -f "${LOCKFILE}"; }
+    trap 'remove_lock' EXIT
+  fi
 
   # Get CA URLs
   CA_DIRECTORY="$(http_request get "${CA}")"
@@ -315,15 +326,19 @@ _openssl() {
 http_request() {
   tempcont="$(_mktemp)"
 
+  if [[ -n "${IP_VERSION:-}" ]]; then
+      ip_version="-${IP_VERSION}"
+  fi
+
   set +e
   if [[ "${1}" = "head" ]]; then
-    statuscode="$(curl -s -w "%{http_code}" -o "${tempcont}" "${2}" -I)"
+    statuscode="$(curl ${ip_version:-} -s -w "%{http_code}" -o "${tempcont}" "${2}" -I)"
     curlret="${?}"
   elif [[ "${1}" = "get" ]]; then
-    statuscode="$(curl -s -w "%{http_code}" -o "${tempcont}" "${2}")"
+    statuscode="$(curl ${ip_version:-} -s -w "%{http_code}" -o "${tempcont}" "${2}")"
     curlret="${?}"
   elif [[ "${1}" = "post" ]]; then
-    statuscode="$(curl -s -w "%{http_code}" -o "${tempcont}" "${2}" -d "${3}")"
+    statuscode="$(curl ${ip_version:-} -s -w "%{http_code}" -o "${tempcont}" "${2}" -d "${3}")"
     curlret="${?}"
   else
     set -e
@@ -340,6 +355,8 @@ http_request() {
     echo >&2
     echo "Details:" >&2
     cat "${tempcont}" >&2
+    echo >&2
+    echo >&2
     rm -f "${tempcont}"
 
     # Wait for hook script to clean the challenge if used
@@ -664,7 +681,13 @@ command_sign_domains() {
     # for now this loads the certificate specific config in a subshell and parses a diff of set variables.
     # we could just source the config file but i decided to go this way to protect people from accidentally overriding
     # variables used internally by this script itself.
-    if [ -f "${CERTDIR}/${domain}/config" ]; then
+    if [[ -n "${DOMAINS_D}" ]]; then
+      certconfig="${DOMAINS_D}/${domain}"
+    else
+      certconfig="${CERTDIR}/${domain}/config"
+    fi
+
+    if [ -f "${certconfig}" ]; then
       echo " + Using certificate specific config file!"
       ORIGIFS="${IFS}"
       IFS=$'\n'
@@ -673,7 +696,7 @@ command_sign_domains() {
         aftervars="$(_mktemp)"
         set > "${beforevars}"
         # shellcheck disable=SC1090
-        . "${CERTDIR}/${domain}/config"
+        . "${certconfig}"
         set > "${aftervars}"
         diff -u "${beforevars}" "${aftervars}" | grep -E '^\+[^+]'
         rm "${beforevars}"
@@ -733,7 +756,12 @@ command_sign_domains() {
     fi
 
     # shellcheck disable=SC2086
-    sign_domain ${line}
+    if [[ "${PARAM_KEEP_GOING:-}" = "yes" ]]; then
+      sign_domain ${line} &
+      wait $! || true
+    else
+      sign_domain ${line}
+    fi
   done
 
   # remove temporary domains.txt file if used
@@ -760,24 +788,29 @@ command_sign_csr() {
   certfile="$(_mktemp)"
   sign_csr "$(< "${csrfile}" )" 3> "${certfile}"
 
-  # get and convert ca cert
-  chainfile="$(_mktemp)"
-  http_request get "$(openssl x509 -in "${certfile}" -noout -text | grep 'CA Issuers - URI:' | cut -d':' -f2-)" > "${chainfile}"
-
-  if ! grep -q "BEGIN CERTIFICATE" "${chainfile}"; then
-    openssl x509 -inform DER -in "${chainfile}" -outform PEM -out "${chainfile}"
-  fi
-
-  # output full chain
+  # print cert
   echo "# CERT #" >&3
   cat "${certfile}" >&3
   echo >&3
-  echo "# CHAIN #" >&3
-  cat "${chainfile}" >&3
+
+  # print chain
+  if [ -n "${PARAM_FULL_CHAIN:-}" ]; then
+    # get and convert ca cert
+    chainfile="$(_mktemp)"
+    http_request get "$(openssl x509 -in "${certfile}" -noout -text | grep 'CA Issuers - URI:' | cut -d':' -f2-)" > "${chainfile}"
+
+    if ! grep -q "BEGIN CERTIFICATE" "${chainfile}"; then
+      openssl x509 -inform DER -in "${chainfile}" -outform PEM -out "${chainfile}"
+    fi
+
+    echo "# CHAIN #" >&3
+    cat "${chainfile}" >&3
+
+    rm "${chainfile}"
+  fi
 
   # cleanup
   rm "${certfile}"
-  rm "${chainfile}"
 
   exit 0
 }
@@ -893,7 +926,7 @@ command_help() {
 command_env() {
   echo "# letsencrypt.sh configuration"
   load_config
-  typeset -p CA LICENSE CERTDIR CHALLENGETYPE DOMAINS_TXT HOOK HOOK_CHAIN RENEW_DAYS ACCOUNT_KEY ACCOUNT_KEY_JSON KEYSIZE WELLKNOWN PRIVATE_KEY_RENEW OPENSSL_CNF CONTACT_EMAIL LOCKFILE
+  typeset -p CA LICENSE CERTDIR CHALLENGETYPE DOMAINS_D DOMAINS_TXT HOOK HOOK_CHAIN RENEW_DAYS ACCOUNT_KEY ACCOUNT_KEY_JSON KEYSIZE WELLKNOWN PRIVATE_KEY_RENEW OPENSSL_CNF CONTACT_EMAIL LOCKFILE
 }
 
 # Main method (parses script arguments and calls command_* methods)
@@ -950,6 +983,24 @@ main() {
         set_command cleanup
         ;;
 
+      # PARAM_Usage: --full-chain (-fc)
+      # PARAM_Description: Print full chain when using --signcsr
+      --full-chain|-fc)
+        PARAM_FULL_CHAIN="1"
+        ;;
+
+      # PARAM_Usage: --ipv4 (-4)
+      # PARAM_Description: Resolve names to IPv4 addresses only
+      --ipv4|-4)
+        PARAM_IP_VERSION="4"
+        ;;
+
+      # PARAM_Usage: --ipv6 (-6)
+      # PARAM_Description: Resolve names to IPv6 addresses only
+      --ipv6|-6)
+        PARAM_IP_VERSION="6"
+        ;;
+
       # PARAM_Usage: --domain (-d) domain.tld
       # PARAM_Description: Use specified domain name(s) instead of domains.txt entry (one certificate!)
       --domain|-d)
@@ -962,6 +1013,11 @@ main() {
          fi
         ;;
 
+      # PARAM_Usage: --keep-going (-g)
+      # PARAM_Description: Keep going after encountering an error while creating/renewing multiple certificates in cron mode
+      --keep-going|-g)
+        PARAM_KEEP_GOING="yes"
+        ;;
 
       # PARAM_Usage: --force (-x)
       # PARAM_Description: Force renew of certificate even if it is longer valid than value in RENEW_DAYS
@@ -969,6 +1025,12 @@ main() {
         PARAM_FORCE="yes"
         ;;
 
+      # PARAM_Usage: --no-lock (-n)
+      # PARAM_Description: Don't use lockfile (potentially dangerous!)
+      --no-lock|-n)
+        PARAM_NO_LOCK="yes"
+        ;;
+
       # PARAM_Usage: --ocsp
       # PARAM_Description: Sets option in CSR indicating OCSP stapling to be mandatory
       --ocsp)