diff --git a/Makefile.am b/Makefile.am
index 9210aa5..276327d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -34,7 +34,7 @@ lib_LTLIBRARIES = pam_yubico.la
 
 pam_yubico_la_SOURCES = pam_yubico.c
 # XXX add -Wl,-x too?  PAM documentation suggests it.
-pam_yubico_la_LIBADD = @LTLIBYUBIKEY_CLIENT@ @LIBLDAP@
+pam_yubico_la_LIBADD = @LTLIBYKCLIENT@ @LIBLDAP@
 pam_yubico_la_LDFLAGS = -module -avoid-version
 
 DEFS = -DDEBUG_PAM @DEFS@
diff --git a/NEWS b/NEWS
index 7d34130..b2fdd08 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,9 @@
 pam_yubico NEWS -- History of user-visible changes.             -*- outline -*-
 
-* Version 1.15 (unreleased)
+* Version 2.0 (unreleased)
+
+** Requires libykclient v2.0 or later.
+See <http://code.google.com/p/yubico-c-client/>.
 
 * Version 1.14 (released 2009-03-24)
 
diff --git a/README b/README
index d74dd70..39e3943 100644
--- a/README
+++ b/README
@@ -50,9 +50,9 @@ Generate the build system using:
 
 == Building ==
 
-You will need to have libyubikey-client (libykclient.h,
-libyubikey-client.so) and libpam-dev (security/pam_appl.h, libpam.so)
-installed.  Get the libyubikey-client library from:
+You will need to have libykclient (ykclient.h, libykclient.so) and
+libpam-dev (security/pam_appl.h, libpam.so) installed.  Get the
+ykclient library from:
 
 http://code.google.com/p/yubico-c-client/
 
diff --git a/configure.ac b/configure.ac
index ef36812..4024c19 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,7 +26,7 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-AC_INIT([pam_yubico], [1.15], [simon@yubico.com])
+AC_INIT([pam_yubico], [2.0], [simon@yubico.com])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([foreign])
@@ -59,8 +59,11 @@ AC_ARG_WITH([ldap],
               [])])
 
 
-AC_LIB_HAVE_LINKFLAGS([yubikey-client],, [#include <libykclient.h>],
-                      [yubikey_client_init ();])
+AC_LIB_HAVE_LINKFLAGS([ykclient],, [#include <ykclient.h>],
+                      [ykclient_init (0);])
+if test "$ac_cv_libykclient" != yes; then
+   AC_MSG_ERROR([[Libykclient not found, get it from http://code.google.com/p/yubico-c-client/]])
+fi
 
 AC_SUBST(PAMDIR, "\$(exec_prefix)/lib/security")
 AC_ARG_WITH(pam-dir,
diff --git a/pam_yubico.c b/pam_yubico.c
index 1728689..0329d3b 100644
--- a/pam_yubico.c
+++ b/pam_yubico.c
@@ -63,7 +63,7 @@
 # endif
 #endif
 
-#include <libykclient.h>
+#include <ykclient.h>
 
 #ifdef HAVE_LIBLDAP
 #include <ldap.h>
@@ -397,7 +397,7 @@ pam_sm_authenticate (pam_handle_t * pamh,
   struct pam_message *pmsg[1], msg[1];
   struct pam_response *resp;
   int nargs = 1;
-  yubikey_client_t ykc = NULL;
+  ykclient_t *ykc = NULL;
   struct cfg cfg;
 
   parse_cfg (flags, argc, argv, &cfg);
@@ -429,17 +429,17 @@ pam_sm_authenticate (pam_handle_t * pamh,
       goto done;
     }
 
-  ykc = yubikey_client_init ();
-  if (!ykc)
+  rc = ykclient_init (&ykc);
+  if (rc != YKCLIENT_OK)
     {
-      DBG (("yubikey_client_init() failed"));
+      DBG (("ykclient_init() failed (%d): %s", rc, ykclient_strerror (rc)));
       retval = PAM_AUTHINFO_UNAVAIL;
       goto done;
     }
 
-  yubikey_client_set_info (ykc, cfg.client_id, 0, NULL);
+  ykclient_set_client (ykc, cfg.client_id, 0, NULL);
   if (cfg.url)
-    yubikey_client_set_url_template (ykc, cfg.url);
+    ykclient_set_url_template (ykc, cfg.url);
 
   if (password == NULL)
     {
@@ -522,18 +522,18 @@ pam_sm_authenticate (pam_handle_t * pamh,
   else
     password = NULL;
 
-  rc = yubikey_client_request (ykc, otp);
+  rc = ykclient_request (ykc, otp);
 
-  DBG (("libyubikey-client return value (%d): %s", rc,
-	yubikey_client_strerror (rc)));
+  DBG (("ykclient return value (%d): %s", rc,
+	ykclient_strerror (rc)));
 
   switch (rc)
     {
-    case YUBIKEY_CLIENT_OK:
+    case YKCLIENT_OK:
       break;
 
-    case YUBIKEY_CLIENT_BAD_OTP:
-    case YUBIKEY_CLIENT_REPLAYED_OTP:
+    case YKCLIENT_BAD_OTP:
+    case YKCLIENT_REPLAYED_OTP:
       retval = PAM_AUTH_ERR;
       goto done;
 
@@ -561,7 +561,7 @@ pam_sm_authenticate (pam_handle_t * pamh,
 
 done:
   if (ykc)
-    yubikey_client_done (&ykc);
+    ykclient_done (&ykc);
   if (cfg.alwaysok && retval != PAM_SUCCESS)
     {
       DBG (("alwaysok needed (otherwise return with %d)", retval));