diff --git a/vendor/github.com/xenolf/lego/acme/challenges.go b/vendor/github.com/xenolf/lego/acme/challenges.go
index 1140b107..d10f82b8 100644
--- a/vendor/github.com/xenolf/lego/acme/challenges.go
+++ b/vendor/github.com/xenolf/lego/acme/challenges.go
@@ -7,9 +7,11 @@ const (
 	// HTTP01 is the "http-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#http
 	// Note: HTTP01ChallengePath returns the URL path to fulfill this challenge
 	HTTP01 = Challenge("http-01")
+
 	// DNS01 is the "dns-01" ACME challenge https://github.com/ietf-wg-acme/acme/blob/master/draft-ietf-acme-acme.md#dns
 	// Note: DNS01Record returns a DNS record which will fulfill this challenge
 	DNS01 = Challenge("dns-01")
+
 	// TLSALPN01 is the "tls-alpn-01" ACME challenge https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-01
 	TLSALPN01 = Challenge("tls-alpn-01")
 )
diff --git a/vendor/github.com/xenolf/lego/acme/client.go b/vendor/github.com/xenolf/lego/acme/client.go
index b8daa751..f9857ebd 100644
--- a/vendor/github.com/xenolf/lego/acme/client.go
+++ b/vendor/github.com/xenolf/lego/acme/client.go
@@ -26,6 +26,9 @@ const (
 	// “new-reg”, “new-authz” and “new-cert” endpoints. From the documentation the
 	// limitation is 20 requests per second, but using 20 as value doesn't work but 18 do
 	overallRequestLimit = 18
+
+	statusValid   = "valid"
+	statusInvalid = "invalid"
 )
 
 // User interface is to be implemented by users of this library.
@@ -41,6 +44,17 @@ type solver interface {
 	Solve(challenge challenge, domain string) error
 }
 
+// Interface for challenges like dns, where we can set a record in advance for ALL challenges.
+// This saves quite a bit of time vs creating the records and solving them serially.
+type preSolver interface {
+	PreSolve(challenge challenge, domain string) error
+}
+
+// Interface for challenges like dns, where we can solve all the challenges before to delete them.
+type cleanup interface {
+	CleanUp(challenge challenge, domain string) error
+}
+
 type validateFunc func(j *jws, domain, uri string, chlng challenge) error
 
 // Client is the user-friendy way to ACME
@@ -374,8 +388,10 @@ DNSNames:
 		}
 	}
 
-	// Add the CSR to the certificate so that it can be used for renewals.
-	cert.CSR = pemEncode(&csr)
+	if cert != nil {
+		// Add the CSR to the certificate so that it can be used for renewals.
+		cert.CSR = pemEncode(&csr)
+	}
 
 	// do not return an empty failures map, because
 	// it would still be a non-nil error value
@@ -396,7 +412,7 @@ DNSNames:
 // the whole certificate will fail.
 func (c *Client) ObtainCertificate(domains []string, bundle bool, privKey crypto.PrivateKey, mustStaple bool) (*CertificateResource, error) {
 	if len(domains) == 0 {
-		return nil, errors.New("No domains to obtain a certificate for")
+		return nil, errors.New("no domains to obtain a certificate for")
 	}
 
 	if bundle {
@@ -489,9 +505,9 @@ func (c *Client) RenewCertificate(cert CertificateResource, bundle, mustStaple b
 	// Start by checking to see if the certificate was based off a CSR, and
 	// use that if it's defined.
 	if len(cert.CSR) > 0 {
-		csr, err := pemDecodeTox509CSR(cert.CSR)
-		if err != nil {
-			return nil, err
+		csr, errP := pemDecodeTox509CSR(cert.CSR)
+		if errP != nil {
+			return nil, errP
 		}
 		newCert, failures := c.ObtainCertificateForCSR(*csr, bundle)
 		return newCert, failures
@@ -524,7 +540,6 @@ func (c *Client) RenewCertificate(cert CertificateResource, bundle, mustStaple b
 }
 
 func (c *Client) createOrderForIdentifiers(domains []string) (orderResource, error) {
-
 	var identifiers []identifier
 	for _, domain := range domains {
 		identifiers = append(identifiers, identifier{Type: "dns", Value: domain})
@@ -548,29 +563,75 @@ func (c *Client) createOrderForIdentifiers(domains []string) (orderResource, err
 	return orderRes, nil
 }
 
+// an authz with the solver we have chosen and the index of the challenge associated with it
+type selectedAuthSolver struct {
+	authz          authorization
+	challengeIndex int
+	solver         solver
+}
+
 // Looks through the challenge combinations to find a solvable match.
 // Then solves the challenges in series and returns.
 func (c *Client) solveChallengeForAuthz(authorizations []authorization) error {
 	failures := make(ObtainError)
 
-	// loop through the resources, basically through the domains.
+	authSolvers := []*selectedAuthSolver{}
+
+	// loop through the resources, basically through the domains. First pass just selects a solver for each authz.
 	for _, authz := range authorizations {
-		if authz.Status == "valid" {
+		if authz.Status == statusValid {
 			// Boulder might recycle recent validated authz (see issue #267)
 			log.Infof("[%s] acme: Authorization already valid; skipping challenge", authz.Identifier.Value)
 			continue
 		}
+		if i, solvr := c.chooseSolver(authz, authz.Identifier.Value); solvr != nil {
+			authSolvers = append(authSolvers, &selectedAuthSolver{
+				authz:          authz,
+				challengeIndex: i,
+				solver:         solvr,
+			})
+		} else {
+			failures[authz.Identifier.Value] = fmt.Errorf("[%s] acme: Could not determine solvers", authz.Identifier.Value)
+		}
+	}
 
-		// no solvers - no solving
-		if i, solver := c.chooseSolver(authz, authz.Identifier.Value); solver != nil {
-			err := solver.Solve(authz.Challenges[i], authz.Identifier.Value)
-			if err != nil {
-				//c.disableAuthz(authz.Identifier)
+	// for all valid presolvers, first submit the challenges so they have max time to propagate
+	for _, item := range authSolvers {
+		authz := item.authz
+		i := item.challengeIndex
+		if presolver, ok := item.solver.(preSolver); ok {
+			if err := presolver.PreSolve(authz.Challenges[i], authz.Identifier.Value); err != nil {
 				failures[authz.Identifier.Value] = err
 			}
-		} else {
-			//c.disableAuthz(authz)
-			failures[authz.Identifier.Value] = fmt.Errorf("[%s] acme: Could not determine solvers", authz.Identifier.Value)
+		}
+	}
+
+	defer func() {
+		// clean all created TXT records
+		for _, item := range authSolvers {
+			if clean, ok := item.solver.(cleanup); ok {
+				if failures[item.authz.Identifier.Value] != nil {
+					// already failed in previous loop
+					continue
+				}
+				err := clean.CleanUp(item.authz.Challenges[item.challengeIndex], item.authz.Identifier.Value)
+				if err != nil {
+					log.Warnf("Error cleaning up %s: %v ", item.authz.Identifier.Value, err)
+				}
+			}
+		}
+	}()
+
+	// finally solve all challenges for real
+	for _, item := range authSolvers {
+		authz := item.authz
+		i := item.challengeIndex
+		if failures[authz.Identifier.Value] != nil {
+			// already failed in previous loop
+			continue
+		}
+		if err := item.solver.Solve(authz.Challenges[i], authz.Identifier.Value); err != nil {
+			failures[authz.Identifier.Value] = err
 		}
 	}
 
@@ -604,7 +665,7 @@ func (c *Client) getAuthzForOrder(order orderResource) ([]authorization, error)
 
 		go func(authzURL string) {
 			var authz authorization
-			_, err := getJSON(authzURL, &authz)
+			_, err := postAsGet(c.jws, authzURL, &authz)
 			if err != nil {
 				errc <- domainError{Domain: authz.Identifier.Value, Error: err}
 				return
@@ -696,7 +757,7 @@ func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr
 		return nil, err
 	}
 
-	if retOrder.Status == "invalid" {
+	if retOrder.Status == statusInvalid {
 		return nil, err
 	}
 
@@ -706,7 +767,7 @@ func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr
 		PrivateKey: privateKeyPem,
 	}
 
-	if retOrder.Status == "valid" {
+	if retOrder.Status == statusValid {
 		// if the certificate is available right away, short cut!
 		ok, err := c.checkCertResponse(retOrder, &certRes, bundle)
 		if err != nil {
@@ -728,7 +789,7 @@ func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr
 		case <-stopTimer.C:
 			return nil, errors.New("certificate polling timed out")
 		case <-retryTick.C:
-			_, err := getJSON(order.URL, &retOrder)
+			_, err := postAsGet(c.jws, order.URL, &retOrder)
 			if err != nil {
 				return nil, err
 			}
@@ -750,10 +811,9 @@ func (c *Client) requestCertificateForCsr(order orderResource, bundle bool, csr
 // should already have the Domain (common name) field populated. If bundle is
 // true, the certificate will be bundled with the issuer's cert.
 func (c *Client) checkCertResponse(order orderMessage, certRes *CertificateResource, bundle bool) (bool, error) {
-
 	switch order.Status {
-	case "valid":
-		resp, err := httpGet(order.Certificate)
+	case statusValid:
+		resp, err := postAsGet(c.jws, order.Certificate, nil)
 		if err != nil {
 			return false, err
 		}
@@ -801,7 +861,7 @@ func (c *Client) checkCertResponse(order orderMessage, certRes *CertificateResou
 
 	case "processing":
 		return false, nil
-	case "invalid":
+	case statusInvalid:
 		return false, errors.New("order has invalid state: invalid")
 	default:
 		return false, nil
@@ -811,7 +871,7 @@ func (c *Client) checkCertResponse(order orderMessage, certRes *CertificateResou
 // getIssuerCertificate requests the issuer certificate
 func (c *Client) getIssuerCertificate(url string) ([]byte, error) {
 	log.Infof("acme: Requesting issuer cert from %s", url)
-	resp, err := httpGet(url)
+	resp, err := postAsGet(c.jws, url, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -854,7 +914,10 @@ func parseLinks(links []string) map[string]string {
 func validate(j *jws, domain, uri string, c challenge) error {
 	var chlng challenge
 
-	hdr, err := postJSON(j, uri, c, &chlng)
+	// Challenge initiation is done by sending a JWS payload containing the
+	// trivial JSON object `{}`. We use an empty struct instance as the postJSON
+	// payload here to achieve this result.
+	hdr, err := postJSON(j, uri, struct{}{}, &chlng)
 	if err != nil {
 		return err
 	}
@@ -863,12 +926,12 @@ func validate(j *jws, domain, uri string, c challenge) error {
 	// Repeatedly check the server for an updated status on our request.
 	for {
 		switch chlng.Status {
-		case "valid":
+		case statusValid:
 			log.Infof("[%s] The server validated our request", domain)
 			return nil
 		case "pending":
 		case "processing":
-		case "invalid":
+		case statusInvalid:
 			return handleChallengeError(chlng)
 		default:
 			return errors.New("the server returned an unexpected state")
@@ -880,11 +943,15 @@ func validate(j *jws, domain, uri string, c challenge) error {
 			// If it doesn't, we'll just poll hard.
 			ra = 5
 		}
+
 		time.Sleep(time.Duration(ra) * time.Second)
 
-		hdr, err = getJSON(uri, &chlng)
+		resp, err := postAsGet(j, uri, &chlng)
 		if err != nil {
 			return err
 		}
+		if resp != nil {
+			hdr = resp.Header
+		}
 	}
 }
diff --git a/vendor/github.com/xenolf/lego/acme/crypto.go b/vendor/github.com/xenolf/lego/acme/crypto.go
index f5ebbf08..5ddeeaec 100644
--- a/vendor/github.com/xenolf/lego/acme/crypto.go
+++ b/vendor/github.com/xenolf/lego/acme/crypto.go
@@ -81,20 +81,20 @@ func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
 			return nil, nil, errors.New("no issuing certificate URL")
 		}
 
-		resp, err := httpGet(issuedCert.IssuingCertificateURL[0])
-		if err != nil {
-			return nil, nil, err
+		resp, errC := httpGet(issuedCert.IssuingCertificateURL[0])
+		if errC != nil {
+			return nil, nil, errC
 		}
 		defer resp.Body.Close()
 
-		issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
-		if err != nil {
-			return nil, nil, err
+		issuerBytes, errC := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+		if errC != nil {
+			return nil, nil, errC
 		}
 
-		issuerCert, err := x509.ParseCertificate(issuerBytes)
-		if err != nil {
-			return nil, nil, err
+		issuerCert, errC := x509.ParseCertificate(issuerBytes)
+		if errC != nil {
+			return nil, nil, errC
 		}
 
 		// Insert it into the slice on position 0
@@ -258,15 +258,6 @@ func pemDecode(data []byte) (*pem.Block, error) {
 	return pemBlock, nil
 }
 
-func pemDecodeTox509(pem []byte) (*x509.Certificate, error) {
-	pemBlock, err := pemDecode(pem)
-	if pemBlock == nil {
-		return nil, err
-	}
-
-	return x509.ParseCertificate(pemBlock.Bytes)
-}
-
 func pemDecodeTox509CSR(pem []byte) (*x509.CertificateRequest, error) {
 	pemBlock, err := pemDecode(pem)
 	if pemBlock == nil {
diff --git a/vendor/github.com/xenolf/lego/acme/dns_challenge.go b/vendor/github.com/xenolf/lego/acme/dns_challenge.go
index c8a35eb8..d9c252e7 100644
--- a/vendor/github.com/xenolf/lego/acme/dns_challenge.go
+++ b/vendor/github.com/xenolf/lego/acme/dns_challenge.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/miekg/dns"
@@ -18,18 +19,30 @@ type preCheckDNSFunc func(fqdn, value string) (bool, error)
 var (
 	// PreCheckDNS checks DNS propagation before notifying ACME that
 	// the DNS challenge is ready.
-	PreCheckDNS preCheckDNSFunc = checkDNSPropagation
-	fqdnToZone                  = map[string]string{}
+	PreCheckDNS  preCheckDNSFunc = checkDNSPropagation
+	fqdnToZone                   = map[string]string{}
+	muFqdnToZone sync.Mutex
 )
 
 const defaultResolvConf = "/etc/resolv.conf"
 
+const (
+	// DefaultPropagationTimeout default propagation timeout
+	DefaultPropagationTimeout = 60 * time.Second
+
+	// DefaultPollingInterval default polling interval
+	DefaultPollingInterval = 2 * time.Second
+
+	// DefaultTTL default TTL
+	DefaultTTL = 120
+)
+
 var defaultNameservers = []string{
 	"google-public-dns-a.google.com:53",
 	"google-public-dns-b.google.com:53",
 }
 
-// RecursiveNameservers are used to pre-check DNS propagations
+// RecursiveNameservers are used to pre-check DNS propagation
 var RecursiveNameservers = getNameservers(defaultResolvConf, defaultNameservers)
 
 // DNSTimeout is used to override the default DNS timeout of 10 seconds.
@@ -59,7 +72,7 @@ func DNS01Record(domain, keyAuth string) (fqdn string, value string, ttl int) {
 	keyAuthShaBytes := sha256.Sum256([]byte(keyAuth))
 	// base64URL encoding without padding
 	value = base64.RawURLEncoding.EncodeToString(keyAuthShaBytes[:sha256.Size])
-	ttl = 120
+	ttl = DefaultTTL
 	fqdn = fmt.Sprintf("_acme-challenge.%s.", domain)
 	return
 }
@@ -71,8 +84,10 @@ type dnsChallenge struct {
 	provider ChallengeProvider
 }
 
-func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
-	log.Infof("[%s] acme: Trying to solve DNS-01", domain)
+// PreSolve just submits the txt record to the dns provider. It does not validate record propagation, or
+// do anything at all with the acme server.
+func (s *dnsChallenge) PreSolve(chlng challenge, domain string) error {
+	log.Infof("[%s] acme: Preparing to solve DNS-01", domain)
 
 	if s.provider == nil {
 		return errors.New("no DNS Provider configured")
@@ -88,12 +103,18 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	if err != nil {
 		return fmt.Errorf("error presenting token: %s", err)
 	}
-	defer func() {
-		err := s.provider.CleanUp(domain, chlng.Token, keyAuth)
-		if err != nil {
-			log.Warnf("Error cleaning up %s: %v ", domain, err)
-		}
-	}()
+
+	return nil
+}
+
+func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
+	log.Infof("[%s] acme: Trying to solve DNS-01", domain)
+
+	// Generate the Key Authorization for the challenge
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
+	if err != nil {
+		return err
+	}
 
 	fqdn, value, _ := DNS01Record(domain, keyAuth)
 
@@ -104,7 +125,7 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	case ChallengeProviderTimeout:
 		timeout, interval = provider.Timeout()
 	default:
-		timeout, interval = 60*time.Second, 2*time.Second
+		timeout, interval = DefaultPropagationTimeout, DefaultPollingInterval
 	}
 
 	err = WaitFor(timeout, interval, func() (bool, error) {
@@ -117,6 +138,15 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	return s.validate(s.jws, domain, chlng.URL, challenge{Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
 }
 
+// CleanUp cleans the challenge
+func (s *dnsChallenge) CleanUp(chlng challenge, domain string) error {
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
+	if err != nil {
+		return err
+	}
+	return s.provider.CleanUp(domain, chlng.Token, keyAuth)
+}
+
 // checkDNSPropagation checks if the expected TXT record has been propagated to all authoritative nameservers.
 func checkDNSPropagation(fqdn, value string) (bool, error) {
 	// Initial attempt to resolve at the recursive NS
@@ -124,6 +154,7 @@ func checkDNSPropagation(fqdn, value string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
+
 	if r.Rcode == dns.RcodeSuccess {
 		// If we see a CNAME here then use the alias
 		for _, rr := range r.Answer {
@@ -167,7 +198,7 @@ func checkAuthoritativeNss(fqdn, value string, nameservers []string) (bool, erro
 		}
 
 		if !found {
-			return false, fmt.Errorf("NS %s did not return the expected TXT record", ns)
+			return false, fmt.Errorf("NS %s did not return the expected TXT record [fqdn: %s]", ns, fqdn)
 		}
 	}
 
@@ -210,7 +241,7 @@ func lookupNameservers(fqdn string) ([]string, error) {
 
 	zone, err := FindZoneByFqdn(fqdn, RecursiveNameservers)
 	if err != nil {
-		return nil, fmt.Errorf("Could not determine the zone: %v", err)
+		return nil, fmt.Errorf("could not determine the zone: %v", err)
 	}
 
 	r, err := dnsQuery(zone, dns.TypeNS, RecursiveNameservers, true)
@@ -227,12 +258,15 @@ func lookupNameservers(fqdn string) ([]string, error) {
 	if len(authoritativeNss) > 0 {
 		return authoritativeNss, nil
 	}
-	return nil, fmt.Errorf("Could not determine authoritative nameservers")
+	return nil, fmt.Errorf("could not determine authoritative nameservers")
 }
 
 // FindZoneByFqdn determines the zone apex for the given fqdn by recursing up the
 // domain labels until the nameserver returns a SOA record in the answer section.
 func FindZoneByFqdn(fqdn string, nameservers []string) (string, error) {
+	muFqdnToZone.Lock()
+	defer muFqdnToZone.Unlock()
+
 	// Do we have it cached?
 	if zone, ok := fqdnToZone[fqdn]; ok {
 		return zone, nil
@@ -249,7 +283,7 @@ func FindZoneByFqdn(fqdn string, nameservers []string) (string, error) {
 
 		// Any response code other than NOERROR and NXDOMAIN is treated as error
 		if in.Rcode != dns.RcodeNameError && in.Rcode != dns.RcodeSuccess {
-			return "", fmt.Errorf("Unexpected response code '%s' for %s",
+			return "", fmt.Errorf("unexpected response code '%s' for %s",
 				dns.RcodeToString[in.Rcode], domain)
 		}
 
@@ -272,7 +306,7 @@ func FindZoneByFqdn(fqdn string, nameservers []string) (string, error) {
 		}
 	}
 
-	return "", fmt.Errorf("Could not find the start of authority")
+	return "", fmt.Errorf("could not find the start of authority")
 }
 
 // dnsMsgContainsCNAME checks for a CNAME answer in msg
diff --git a/vendor/github.com/xenolf/lego/acme/http.go b/vendor/github.com/xenolf/lego/acme/http.go
index 8d7ee51e..8343b369 100644
--- a/vendor/github.com/xenolf/lego/acme/http.go
+++ b/vendor/github.com/xenolf/lego/acme/http.go
@@ -42,12 +42,14 @@ var (
 )
 
 const (
-	// defaultGoUserAgent is the Go HTTP package user agent string. Too
-	// bad it isn't exported. If it changes, we should update it here, too.
-	defaultGoUserAgent = "Go-http-client/1.1"
-
 	// ourUserAgent is the User-Agent of this underlying library package.
-	ourUserAgent = "xenolf-acme"
+	// NOTE: Update this with each tagged release.
+	ourUserAgent = "xenolf-acme/1.2.1"
+
+	// ourUserAgentComment is part of the UA comment linked to the version status of this underlying library package.
+	// values: detach|release
+	// NOTE: Update this with each tagged release.
+	ourUserAgentComment = "detach"
 
 	// caCertificatesEnvVar is the environment variable name that can be used to
 	// specify the path to PEM encoded CA Certificates that can be used to
@@ -148,59 +150,63 @@ func getJSON(uri string, respBody interface{}) (http.Header, error) {
 func postJSON(j *jws, uri string, reqBody, respBody interface{}) (http.Header, error) {
 	jsonBytes, err := json.Marshal(reqBody)
 	if err != nil {
-		return nil, errors.New("Failed to marshal network message")
+		return nil, errors.New("failed to marshal network message")
 	}
 
-	resp, err := j.post(uri, jsonBytes)
-	if err != nil {
-		return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
+	resp, err := post(j, uri, jsonBytes, respBody)
+	if resp == nil {
+		return nil, err
 	}
 
 	defer resp.Body.Close()
 
+	return resp.Header, err
+}
+
+func postAsGet(j *jws, uri string, respBody interface{}) (*http.Response, error) {
+	return post(j, uri, []byte{}, respBody)
+}
+
+func post(j *jws, uri string, reqBody []byte, respBody interface{}) (*http.Response, error) {
+	resp, err := j.post(uri, reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("failed to post JWS message. -> %v", err)
+	}
+
 	if resp.StatusCode >= http.StatusBadRequest {
-
-		err := handleHTTPError(resp)
-
+		err = handleHTTPError(resp)
 		switch err.(type) {
-
 		case NonceError:
-
 			// Retry once if the nonce was invalidated
 
-			retryResp, err := j.post(uri, jsonBytes)
-			if err != nil {
-				return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
+			retryResp, errP := j.post(uri, reqBody)
+			if errP != nil {
+				return nil, fmt.Errorf("failed to post JWS message. -> %v", errP)
 			}
 
-			defer retryResp.Body.Close()
-
 			if retryResp.StatusCode >= http.StatusBadRequest {
-				return retryResp.Header, handleHTTPError(retryResp)
+				return retryResp, handleHTTPError(retryResp)
 			}
 
 			if respBody == nil {
-				return retryResp.Header, nil
+				return retryResp, nil
 			}
 
-			return retryResp.Header, json.NewDecoder(retryResp.Body).Decode(respBody)
-
+			return retryResp, json.NewDecoder(retryResp.Body).Decode(respBody)
 		default:
-			return resp.Header, err
-
+			return resp, err
 		}
-
 	}
 
 	if respBody == nil {
-		return resp.Header, nil
+		return resp, nil
 	}
 
-	return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
+	return resp, json.NewDecoder(resp.Body).Decode(respBody)
 }
 
 // userAgent builds and returns the User-Agent string to use in requests.
 func userAgent() string {
-	ua := fmt.Sprintf("%s %s (%s; %s) %s", UserAgent, ourUserAgent, runtime.GOOS, runtime.GOARCH, defaultGoUserAgent)
+	ua := fmt.Sprintf("%s %s (%s; %s; %s)", UserAgent, ourUserAgent, ourUserAgentComment, runtime.GOOS, runtime.GOARCH)
 	return strings.TrimSpace(ua)
 }
diff --git a/vendor/github.com/xenolf/lego/acme/http_challenge_server.go b/vendor/github.com/xenolf/lego/acme/http_challenge_server.go
index 319e2618..9c595d7f 100644
--- a/vendor/github.com/xenolf/lego/acme/http_challenge_server.go
+++ b/vendor/github.com/xenolf/lego/acme/http_challenge_server.go
@@ -35,7 +35,7 @@ func (s *HTTPProviderServer) Present(domain, token, keyAuth string) error {
 	var err error
 	s.listener, err = net.Listen("tcp", net.JoinHostPort(s.iface, s.port))
 	if err != nil {
-		return fmt.Errorf("Could not start HTTP server for challenge -> %v", err)
+		return fmt.Errorf("could not start HTTP server for challenge -> %v", err)
 	}
 
 	s.done = make(chan bool)
@@ -62,20 +62,31 @@ func (s *HTTPProviderServer) serve(domain, token, keyAuth string) {
 	mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
 		if strings.HasPrefix(r.Host, domain) && r.Method == http.MethodGet {
 			w.Header().Add("Content-Type", "text/plain")
-			w.Write([]byte(keyAuth))
+			_, err := w.Write([]byte(keyAuth))
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
 			log.Infof("[%s] Served key authentication", domain)
 		} else {
 			log.Warnf("Received request for domain %s with method %s but the domain did not match any challenge. Please ensure your are passing the HOST header properly.", r.Host, r.Method)
-			w.Write([]byte("TEST"))
+			_, err := w.Write([]byte("TEST"))
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
 		}
 	})
 
-	httpServer := &http.Server{
-		Handler: mux,
-	}
+	httpServer := &http.Server{Handler: mux}
+
 	// Once httpServer is shut down we don't want any lingering
 	// connections, so disable KeepAlives.
 	httpServer.SetKeepAlivesEnabled(false)
-	httpServer.Serve(s.listener)
+
+	err := httpServer.Serve(s.listener)
+	if err != nil {
+		log.Println(err)
+	}
 	s.done <- true
 }
diff --git a/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge.go b/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge.go
index d8035199..cc70c350 100644
--- a/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge.go
+++ b/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge.go
@@ -12,8 +12,8 @@ import (
 )
 
 // idPeAcmeIdentifierV1 is the SMI Security for PKIX Certification Extension OID referencing the ACME extension.
-// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-01#section-5.1
-var idPeAcmeIdentifierV1 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 30, 1}
+// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-05#section-5.1
+var idPeAcmeIdentifierV1 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 31}
 
 type tlsALPNChallenge struct {
 	jws      *jws
@@ -58,7 +58,7 @@ func TLSALPNChallengeBlocks(domain, keyAuth string) ([]byte, []byte, error) {
 
 	// Add the keyAuth digest as the acmeValidation-v1 extension
 	// (marked as critical such that it won't be used by non-ACME software).
-	// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-01#section-3
+	// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-05#section-3
 	extensions := []pkix.Extension{
 		{
 			Id:       idPeAcmeIdentifierV1,
diff --git a/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge_server.go b/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge_server.go
index 8d33668e..ee06a16d 100644
--- a/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge_server.go
+++ b/vendor/github.com/xenolf/lego/acme/tls_alpn_challenge_server.go
@@ -3,6 +3,7 @@ package acme
 import (
 	"crypto/tls"
 	"fmt"
+	"log"
 	"net"
 	"net/http"
 )
@@ -65,7 +66,10 @@ func (t *TLSALPNProviderServer) Present(domain, token, keyAuth string) error {
 
 	// Shut the server down when we're finished.
 	go func() {
-		http.Serve(t.listener, nil)
+		err := http.Serve(t.listener, nil)
+		if err != nil {
+			log.Println(err)
+		}
 	}()
 
 	return nil
diff --git a/vendor/github.com/xenolf/lego/acme/utils.go b/vendor/github.com/xenolf/lego/acme/utils.go
index 2fa0db30..f3160806 100644
--- a/vendor/github.com/xenolf/lego/acme/utils.go
+++ b/vendor/github.com/xenolf/lego/acme/utils.go
@@ -3,16 +3,20 @@ package acme
 import (
 	"fmt"
 	"time"
+
+	"github.com/xenolf/lego/log"
 )
 
 // WaitFor polls the given function 'f', once every 'interval', up to 'timeout'.
 func WaitFor(timeout, interval time.Duration, f func() (bool, error)) error {
+	log.Infof("Wait [timeout: %s, interval: %s]", timeout, interval)
+
 	var lastErr string
-	timeup := time.After(timeout)
+	timeUp := time.After(timeout)
 	for {
 		select {
-		case <-timeup:
-			return fmt.Errorf("Time limit exceeded. Last error: %s", lastErr)
+		case <-timeUp:
+			return fmt.Errorf("time limit exceeded: last error: %s", lastErr)
 		default:
 		}
 
diff --git a/vendor/manifest b/vendor/manifest
index 998f2cfa..c2b2f3d4 100644
--- a/vendor/manifest
+++ b/vendor/manifest
@@ -170,7 +170,7 @@
 			"importpath": "github.com/xenolf/lego/acme",
 			"repository": "https://github.com/xenolf/lego",
 			"vcs": "git",
-			"revision": "04e2d74406d42a3727e7a132c1a39735ac527f51",
+			"revision": "4e842a5eb6dcb9520e03db70cd5896f1df14b72a",
 			"branch": "master",
 			"path": "/acme",
 			"notests": true