diff --git a/caddy/caddy.go b/caddy/caddy.go
index 5d1cd9c2..734e984d 100644
--- a/caddy/caddy.go
+++ b/caddy/caddy.go
@@ -1,4 +1,5 @@
-// Package caddy implements the Caddy web server as a service.
+// Package caddy implements the Caddy web server as a service
+// in your own Go programs.
 //
 // To use this package, follow a few simple steps:
 //
diff --git a/caddy/letsencrypt/letsencrypt.go b/caddy/letsencrypt/letsencrypt.go
index 769370e9..a115d91b 100644
--- a/caddy/letsencrypt/letsencrypt.go
+++ b/caddy/letsencrypt/letsencrypt.go
@@ -72,7 +72,11 @@ func Activate(configs []server.Config) ([]server.Config, error) {
 	// set up redirects
 	configs = MakePlaintextRedirects(configs)
 
-	// renew all relevant certificates that need renewal; TODO: handle errors
+	// renew all relevant certificates that need renewal. this is important
+	// to do right away for a couple reasons, mainly because each restart,
+	// the renewal ticker is reset, so if restarts happen more often than
+	// the ticker interval, renewals would never happen. but doing
+	// it right away at start guarantees that renewals aren't missed.
 	renewCertificates(configs, false)
 
 	// keep certificates renewed and OCSP stapling updated
@@ -127,7 +131,7 @@ func ObtainCerts(configs []server.Config, optPort string) error {
 			}
 
 		Obtain:
-			certificate, failures := client.ObtainCertificate([]string{cfg.Host}, true)
+			certificate, failures := client.ObtainCertificate([]string{cfg.Host}, true, nil)
 			if len(failures) == 0 {
 				// Success - immediately save the certificate resource
 				err := saveCertResource(certificate)
@@ -289,11 +293,9 @@ func HostQualifies(hostname string) bool {
 		strings.TrimSpace(hostname) != "" &&
 		net.ParseIP(hostname) == nil && // cannot be an IP address, see: https://community.letsencrypt.org/t/certificate-for-static-ip/84/2?u=mholt
 
-		// TODO: net.ParseIP also catches the two variants without brackets
-		hostname != "[::]" && // before parsing
-		hostname != "::" && // after parsing
-		hostname != "[::1]" && // before parsing
-		hostname != "::1" // after parsing
+		// These special cases can sneak through if specified with -host and with empty/no Caddyfile
+		hostname != "[::]" &&
+		hostname != "[::1]"
 }
 
 // existingCertAndKey returns true if the host has a certificate
@@ -335,8 +337,8 @@ func newClientPort(leEmail, port string) (*acme.Client, error) {
 	if err != nil {
 		return nil, err
 	}
-	client.SetHTTPPort(port)
-	client.SetTLSPort(port)
+	client.SetHTTPAddress(":" + port)
+	client.SetTLSAddress(":" + port)
 	client.ExcludeChallenges([]string{"tls-sni-01", "dns-01"}) // We can only guarantee http-01 at this time
 
 	// If not registered, the user must register an account with the CA
diff --git a/caddy/letsencrypt/maintain.go b/caddy/letsencrypt/maintain.go
index d9ac45e9..0fca4ad4 100644
--- a/caddy/letsencrypt/maintain.go
+++ b/caddy/letsencrypt/maintain.go
@@ -49,7 +49,7 @@ func maintainAssets(configs []server.Config, stopChan chan struct{}) {
 		case <-ocspTicker.C:
 			for bundle, oldResp := range ocspCache {
 				// start checking OCSP staple about halfway through validity period for good measure
-				refreshTime := oldResp.ThisUpdate.Add(oldResp.NextUpdate.Sub(oldResp.ThisUpdate) / 10)
+				refreshTime := oldResp.ThisUpdate.Add(oldResp.NextUpdate.Sub(oldResp.ThisUpdate) / 2)
 				if time.Now().After(refreshTime) {
 					_, newResp, err := acme.GetOCSPForCert(*bundle)
 					if err != nil {
@@ -112,8 +112,8 @@ func renewCertificates(configs []server.Config, useCustomPort bool) (int, []erro
 		// Directly convert it to days for the following checks.
 		daysLeft := int(expTime.Sub(time.Now().UTC()).Hours() / 24)
 
-		// Renew with two weeks or less remaining.
-		if daysLeft <= 14 {
+		// Renew if getting close to expiration.
+		if daysLeft <= renewDaysBefore {
 			log.Printf("[INFO] Certificate for %s has %d days remaining; attempting renewal", cfg.Host, daysLeft)
 			var client *acme.Client
 			if useCustomPort {
@@ -164,11 +164,13 @@ func renewCertificates(configs []server.Config, useCustomPort bool) (int, []erro
 
 			saveCertResource(newCertMeta)
 			n++
-		} else if daysLeft <= 21 {
-			// Warn on 21 days remaining. TODO: Just do this once...
-			log.Printf("[WARNING] Certificate for %s has %d days remaining; will automatically renew when 14 days remain\n", cfg.Host, daysLeft)
+		} else if daysLeft <= renewDaysBefore+7 && daysLeft >= renewDaysBefore+6 {
+			log.Printf("[WARNING] Certificate for %s has %d days remaining; will automatically renew when %d days remain\n", cfg.Host, daysLeft, renewDaysBefore)
 		}
 	}
 
 	return n, errs
 }
+
+// renewDaysBefore is how many days before expiration to renew certificates.
+const renewDaysBefore = 14