diff --git a/DESCRIPTION b/DESCRIPTION
index fc3f85077..06c3155d5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: nanonext
 Type: Package
 Title: NNG (Nanomsg Next Gen) Lightweight Messaging Library
-Version: 0.13.6.9000
+Version: 0.13.6.9002
 Description: R binding for NNG (Nanomsg Next Gen), a successor to ZeroMQ. NNG is
     a socket library implementing 'Scalability Protocols', a reliable,
     high-performance standard for common communications patterns including
@@ -26,10 +26,14 @@ License: GPL (>= 3)
 BugReports: https://github.com/shikokuchuo/nanonext/issues
 URL: https://shikokuchuo.net/nanonext/, https://github.com/shikokuchuo/nanonext/
 Encoding: UTF-8
-SystemRequirements: 'libnng' >= 1.5 and 'libmbedtls' >= 2.5, or 'cmake' to
+SystemRequirements: 'libnng' >= 1.6 and 'libmbedtls' >= 2.5, or 'cmake' to
     compile NNG and/or Mbed TLS included in package sources
 Depends: 
     R (>= 3.5)
+Imports:
+    later
+LinkingTo: 
+    later
 Suggests: 
     knitr,
     markdown
diff --git a/NAMESPACE b/NAMESPACE
index a9f83b67f..f66fa746b 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -75,6 +75,7 @@ export(recv_aio)
 export(recv_aio_signal)
 export(reply)
 export(request)
+export(request2)
 export(request_signal)
 export(send)
 export(send_aio)
@@ -96,6 +97,7 @@ export(until_)
 export(wait)
 export(wait_)
 export(write_cert)
+importFrom(later,later)
 importFrom(stats,start)
 importFrom(tools,md5sum)
 importFrom(utils,.DollarNames)
diff --git a/NEWS.md b/NEWS.md
index 032f74ee3..4aeb74dd6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,13 @@
-# nanonext 0.13.6 (development)
+# nanonext 0.13.6.9002 (development)
+
+#### New Features
+
+* Integrates with the `later` package to provide the foundation for truly event-driven (non-polling) promises (thanks @jcheng5 for the initial prototype in #28), where side-effects are enacted asynchronously upon aio completion.
+* Adds `request2()` for creating a request that may be turned into an event-driven promise.
+
+#### Updates
+
+* Updates minimum 'libnng' version requirement to v1.6.0 (if a suitable system-installed version is not found, the bundled version is compiled from source).
 
 # nanonext 0.13.6
 
diff --git a/R/context.R b/R/context.R
index 0a70df53d..6aa92551d 100644
--- a/R/context.R
+++ b/R/context.R
@@ -269,3 +269,21 @@ request_signal <- function(context,
                                          "integer", "logical", "numeric", "raw", "string"),
                            timeout = NULL)
   data <- .Call(rnng_request_signal, context, data, cv, send_mode, recv_mode, timeout, environment())
+
+#' Request2 (RPC Client for Req/Rep Protocol)
+#'
+#' \strong{request2} is the next generation request function that optionally
+#'     takes a condition variable for signalling, and supports event-driven
+#'     promises.
+#'
+#' @rdname request
+#' @export
+#'
+request2 <- function(context,
+                     data,
+                     cv = NULL,
+                     send_mode = c("serial", "raw", "next"),
+                     recv_mode = c("serial", "character", "complex", "double",
+                                   "integer", "logical", "numeric", "raw", "string"),
+                     timeout = NULL)
+  data <- .Call(rnng_request_promise, context, data, cv, send_mode, recv_mode, timeout, environment())
diff --git a/R/nanonext-package.R b/R/nanonext-package.R
index fff6f714a..c5cf6c148 100644
--- a/R/nanonext-package.R
+++ b/R/nanonext-package.R
@@ -92,6 +92,7 @@
 #' @author Charlie Gao \email{charlie.gao@@shikokuchuo.net}
 #'     (\href{https://orcid.org/0000-0002-0750-061X}{ORCID})
 #'
+#' @importFrom later later
 #' @importFrom stats start
 #' @importFrom tools md5sum
 #' @importFrom utils .DollarNames
diff --git a/README.Rmd b/README.Rmd
index 381fba95f..55312b09c 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -149,7 +149,7 @@ vignette("nanonext", package = "nanonext")
 
 #### Linux / Mac / Solaris
 
-Installation from source requires 'libnng' >= v1.5.0 and 'libmbedtls' >= 2.5.0 (suitable installations are automatically detected), or else 'cmake' to compile 'libnng' v1.7.3 and 'libmbedtls' v3.6.0 LTS included within the package sources.
+Installation from source requires 'libnng' >= v1.6.0 and 'libmbedtls' >= 2.5.0 (suitable installations are automatically detected), or else 'cmake' to compile 'libnng' v1.7.3 and 'libmbedtls' v3.6.0 LTS included within the package sources.
 
 **It is recommended for optimal performance and stability to let the package automatically compile bundled versions of 'libmbedtls' and 'libnng' during installation.** To ensure the libraries are compiled from source even if system installations are present, set the `NANONEXT_LIBS` environment variable prior to installation e.g. by `Sys.setenv(NANONEXT_LIBS = 1)`.
 
@@ -169,6 +169,7 @@ We would like to acknowledge in particular:
 
 - [Garrett D'Amore](https://github.com/gdamore), author of the NNG library, for generous advice and for implementing a feature request specifically for a more efficient 'aio' implementation in `nanonext`.
 - The [R Consortium](https://www.r-consortium.org/) for funding the development of the secure TLS capabilities in the package, and [Henrik Bengtsson](https://github.com/HenrikBengtsson) and [Will Landau](https://github.com/wlandau/)'s roles in making this possible.
+- [Joe Cheng](https://github.com/jcheng5/) for prototyping the integration of `nanonext` with `later` to support the next generation of completely event-driven promises in `mirai`.
 - [R Core](https://www.r-project.org/contributors.html) for various auxiliary functions for serialisation and raw / character conversion, which have been adopted by the package.
 - [Luke Tierney](https://github.com/ltierney/) and [Mike Cheng](https://github.com/coolbutuseless) for meticulous documentation of the R serialization mechanism, which led to the package's own implementation of a low-level interface to R serialization.
 - [Jeroen Ooms](https://github.com/jeroen) - for his 'Anticonf (tm)' configure script, on which our original 'configure' was based, although much modified since.
diff --git a/README.md b/README.md
index 7533e483d..995103e9f 100644
--- a/README.md
+++ b/README.md
@@ -178,7 +178,7 @@ vignette("nanonext", package = "nanonext")
 
 #### Linux / Mac / Solaris
 
-Installation from source requires ‘libnng’ \>= v1.5.0 and ‘libmbedtls’
+Installation from source requires ‘libnng’ \>= v1.6.0 and ‘libmbedtls’
 \>= 2.5.0 (suitable installations are automatically detected), or else
 ‘cmake’ to compile ‘libnng’ v1.7.3 and ‘libmbedtls’ v3.6.0 LTS included
 within the package sources.
@@ -221,6 +221,9 @@ We would like to acknowledge in particular:
   development of the secure TLS capabilities in the package, and [Henrik
   Bengtsson](https://github.com/HenrikBengtsson) and [Will
   Landau](https://github.com/wlandau/)’s roles in making this possible.
+- [Joe Cheng](https://github.com/jcheng5/) for prototyping the
+  integration of `nanonext` with `later` to support the next generation
+  of completely event-driven promises in `mirai`.
 - [R Core](https://www.r-project.org/contributors.html) for various
   auxiliary functions for serialisation and raw / character conversion,
   which have been adopted by the package.
diff --git a/configure b/configure
index 88a9e1be4..5c8ab0809 100755
--- a/configure
+++ b/configure
@@ -128,7 +128,7 @@ fi
 
 echo "#include <nng/nng.h>
 int main() {
-#if NNG_MAJOR_VERSION < 1 || NNG_MAJOR_VERSION == 1 && NNG_MINOR_VERSION < 5
+#if NNG_MAJOR_VERSION < 1 || NNG_MAJOR_VERSION == 1 && NNG_MINOR_VERSION < 6
     *(void *) 0 = 0;
 #endif
 }" | ${CC} ${NNG_CFLAGS} -xc - -o /dev/null > /dev/null 2>&1
@@ -140,7 +140,7 @@ fi
 
 if [ $? -ne 0 ]
 then
-  echo "No existing 'libnng' >= 1.5 found"
+  echo "No existing 'libnng' >= 1.6 found"
   echo "Detecting 'cmake'..."
   which cmake
   if [ $? -ne 0 ]
diff --git a/man/request.Rd b/man/request.Rd
index dccf3fca7..c1c1c475c 100644
--- a/man/request.Rd
+++ b/man/request.Rd
@@ -3,6 +3,7 @@
 \name{request}
 \alias{request}
 \alias{request_signal}
+\alias{request2}
 \title{Request over Context (RPC Client for Req/Rep Protocol)}
 \usage{
 request(
@@ -23,6 +24,16 @@ request_signal(
     "numeric", "raw", "string"),
   timeout = NULL
 )
+
+request2(
+  context,
+  data,
+  cv = NULL,
+  send_mode = c("serial", "raw", "next"),
+  recv_mode = c("serial", "character", "complex", "double", "integer", "logical",
+    "numeric", "raw", "string"),
+  timeout = NULL
+)
 }
 \arguments{
 \item{context}{a Context.}
@@ -57,6 +68,10 @@ Implements a caller/client for the req node of the req/rep protocol. Sends
 
 A signalling version of the function takes a 'conditionVariable' as an
     additional argument and signals it when the async receive is complete.
+
+\strong{request2} is the next generation request function that optionally
+    takes a condition variable for signalling, and supports event-driven
+    promises.
 }
 \details{
 Sending the request and receiving the result are both performed
diff --git a/src/aio.c b/src/aio.c
index 97606f517..d8dc8b2a1 100644
--- a/src/aio.c
+++ b/src/aio.c
@@ -20,6 +20,7 @@
 #define NANONEXT_SUPPLEMENTALS
 #define NANONEXT_SIGNALS
 #include "nanonext.h"
+#include "later_shim.h"
 
 // internals -------------------------------------------------------------------
 
@@ -159,14 +160,7 @@ static void saio_complete(void *arg) {
   const int res = nng_aio_result(saio->aio);
   if (res)
     nng_msg_free(nng_aio_get_msg(saio->aio));
-
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_lock(shr_mtx);
-  saio->result = res - !res;
-  nng_mtx_unlock(shr_mtx);
-#else
   saio->result = res - !res;
-#endif
 
 }
 
@@ -184,14 +178,7 @@ static void isaio_complete(void *arg) {
   const int res = nng_aio_result(iaio->aio);
   if (iaio->data != NULL)
     R_Free(iaio->data);
-
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_lock(shr_mtx);
   iaio->result = res - !res;
-  nng_mtx_unlock(shr_mtx);
-#else
-  iaio->result = res - !res;
-#endif
 
 }
 
@@ -202,13 +189,7 @@ static void raio_complete(void *arg) {
   if (res == 0)
     raio->data = nng_aio_get_msg(raio->aio);
 
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_lock(shr_mtx);
-  raio->result = res - !res;
-  nng_mtx_unlock(shr_mtx);
-#else
   raio->result = res - !res;
-#endif
 
 }
 
@@ -251,18 +232,57 @@ static void request_complete_signal(void *arg) {
 
 }
 
+static void raio_invoke_cb(void *arg) {
+  SEXP call, cb = (SEXP) arg;
+  PROTECT(call = Rf_lcons(cb, R_NilValue));
+  (void) Rf_eval(call, R_GlobalEnv);
+  UNPROTECT(1);
+}
+
+static void raio_complete_cb(void *arg) {
+
+  nano_aio *raio = (nano_aio *) arg;
+  const int res = nng_aio_result(raio->aio);
+  if (res == 0)
+    raio->data = nng_aio_get_msg(raio->aio);
+  raio->result = res - !res;
+
+  nano_aio *saio = (nano_aio *) raio->next;
+  SEXP ax = CADR(ATTRIB((SEXP) saio->data));
+  if (ax != R_NilValue)
+    later2(raio_invoke_cb, ax, 0);
+
+}
+
+static void request_complete_cb(void *arg) {
+
+  nano_aio *raio = (nano_aio *) arg;
+  nano_aio *saio = (nano_aio *) raio->next;
+  nano_cv *ncv = (nano_cv *) saio->next;
+  nng_cv *cv = ncv->cv;
+  nng_mtx *mtx = ncv->mtx;
+
+  const int res = nng_aio_result(raio->aio);
+  if (res == 0)
+    raio->data = nng_aio_get_msg(raio->aio);
+
+  nng_mtx_lock(mtx);
+  raio->result = res - !res;
+  ncv->condition++;
+  nng_cv_wake(cv);
+  nng_mtx_unlock(mtx);
+
+  SEXP ax = CADR(ATTRIB((SEXP) saio->data));
+  if (ax != R_NilValue)
+    later2(raio_invoke_cb, ax, 0);
+
+}
+
 static void iraio_complete(void *arg) {
 
   nano_aio *iaio = (nano_aio *) arg;
   const int res = nng_aio_result(iaio->aio);
-
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_lock(shr_mtx);
-  iaio->result = res - !res;
-  nng_mtx_unlock(shr_mtx);
-#else
   iaio->result = res - !res;
-#endif
 
 }
 
@@ -310,13 +330,12 @@ static void request_finalizer(SEXP xptr) {
   if (R_ExternalPtrAddr(xptr) == NULL) return;
   nano_aio *xp = (nano_aio *) R_ExternalPtrAddr(xptr);
   nano_aio *saio = (nano_aio *) xp->next;
-#ifdef NANONEXT_LEGACY_NNG
-  nng_ctx_close(*(nng_ctx *) saio->data);
-#endif
   nng_aio_free(saio->aio);
   nng_aio_free(xp->aio);
   if (xp->data != NULL)
     nng_msg_free((nng_msg *) xp->data);
+  if (saio->data != NULL)
+    R_ReleaseObject((SEXP) saio->data);
   R_Free(saio);
   R_Free(xp);
 
@@ -390,15 +409,7 @@ SEXP rnng_aio_result(SEXP env) {
 
   nano_aio *saio = (nano_aio *) R_ExternalPtrAddr(aio);
 
-#ifdef NANONEXT_LEGACY_NNG
-  int res;
-  nng_mtx_lock(shr_mtx);
-  res = saio->result;
-  nng_mtx_unlock(shr_mtx);
-  if (res == 0)
-#else
   if (nng_aio_busy(saio->aio))
-#endif
     return nano_unresolved;
 
   if (saio->result > 0)
@@ -422,15 +433,7 @@ SEXP rnng_aio_get_msg(SEXP env) {
 
   nano_aio *raio = (nano_aio *) R_ExternalPtrAddr(aio);
 
-#ifdef NANONEXT_LEGACY_NNG
-  int res;
-  nng_mtx_lock(shr_mtx);
-  res = raio->result;
-  nng_mtx_unlock(shr_mtx);
-  if (res == 0)
-#else
   if (nng_aio_busy(raio->aio))
-#endif
     return nano_unresolved;
 
   if (raio->result > 0)
@@ -595,15 +598,7 @@ SEXP rnng_unresolved2(SEXP aio) {
 
   nano_aio *aiop = (nano_aio *) R_ExternalPtrAddr(coreaio);
 
-#ifdef NANONEXT_LEGACY_NNG
-  int res;
-  nng_mtx_lock(shr_mtx);
-  res = aiop->result;
-  nng_mtx_unlock(shr_mtx);
-  return Rf_ScalarLogical(!res);
-#else
   return Rf_ScalarLogical(nng_aio_busy(aiop->aio));
-#endif
 
 }
 
@@ -947,15 +942,7 @@ SEXP rnng_aio_http(SEXP env, SEXP response, SEXP type) {
 
   nano_aio *haio = (nano_aio *) R_ExternalPtrAddr(aio);
 
-#ifdef NANONEXT_LEGACY_NNG
-  int res;
-  nng_mtx_lock(shr_mtx);
-  res = haio->result;
-  nng_mtx_unlock(shr_mtx);
-  if (res == 0)
-#else
   if (nng_aio_busy(haio->aio))
-#endif
     return nano_unresolved;
 
   if (haio->result > 0)
@@ -1212,7 +1199,8 @@ SEXP rnng_ncurl_session_close(SEXP session) {
 // request ---------------------------------------------------------------------
 
 SEXP rnng_request_impl(const SEXP con, const SEXP data, const SEXP sendmode,
-                       const SEXP recvmode, const SEXP timeout, const SEXP clo, nano_cv *ncv) {
+                       const SEXP recvmode, const SEXP timeout, const SEXP clo,
+                       nano_cv *ncv, const int promises) {
 
   const nng_duration dur = timeout == R_NilValue ? NNG_DURATION_DEFAULT : (nng_duration) Rf_asInteger(timeout);
   const int mod = nano_matcharg(recvmode);
@@ -1234,9 +1222,6 @@ SEXP rnng_request_impl(const SEXP con, const SEXP data, const SEXP sendmode,
   }
 
   saio = R_Calloc(1, nano_aio);
-#ifdef NANONEXT_LEGACY_NNG
-  saio->data = ctx;
-#endif
   saio->next = ncv;
 
   if ((xc = nng_msg_alloc(&msg, 0)))
@@ -1252,11 +1237,20 @@ SEXP rnng_request_impl(const SEXP con, const SEXP data, const SEXP sendmode,
   nng_ctx_send(*ctx, saio->aio);
 
   raio = R_Calloc(1, nano_aio);
+  PROTECT(env = Rf_allocSExp(ENVSXP));
   raio->type = RECVAIO;
   raio->mode = mod;
   raio->next = saio;
+  if (promises) {
+    R_PreserveObject(env);
+    saio->data = env;
+  }
 
-  if ((xc = nng_aio_alloc(&raio->aio, signal ? request_complete_signal : raio_complete, raio)))
+  if ((xc = nng_aio_alloc(&raio->aio,
+                          promises ?
+                            (signal ? request_complete_cb : raio_complete_cb) :
+                            (signal ? request_complete_signal : raio_complete),
+                          raio)))
     goto exitlevel2;
 
   nng_aio_set_timeout(raio->aio, dur);
@@ -1266,7 +1260,6 @@ SEXP rnng_request_impl(const SEXP con, const SEXP data, const SEXP sendmode,
   PROTECT(aio = R_MakeExternalPtr(raio, nano_AioSymbol, R_NilValue));
   R_RegisterCFinalizerEx(aio, request_finalizer, TRUE);
 
-  PROTECT(env = Rf_allocSExp(ENVSXP));
   NANO_CLASS(env, "recvAio");
   Rf_defineVar(nano_AioSymbol, aio, env);
 
@@ -1280,6 +1273,7 @@ SEXP rnng_request_impl(const SEXP con, const SEXP data, const SEXP sendmode,
   return env;
 
   exitlevel2:
+  UNPROTECT(1);
   R_Free(raio);
   nng_aio_free(saio->aio);
   exitlevel1:
@@ -1294,7 +1288,7 @@ SEXP rnng_request(SEXP con, SEXP data, SEXP sendmode, SEXP recvmode, SEXP timeou
   if (R_ExternalPtrTag(con) != nano_ContextSymbol)
     Rf_error("'con' is not a valid Context");
 
-  return rnng_request_impl(con, data, sendmode, recvmode, timeout, clo, NULL);
+  return rnng_request_impl(con, data, sendmode, recvmode, timeout, clo, NULL, 0);
 
 }
 
@@ -1306,7 +1300,18 @@ SEXP rnng_request_signal(SEXP con, SEXP data, SEXP cvar, SEXP sendmode, SEXP rec
     Rf_error("'cv' is not a valid Condition Variable");
   nano_cv *ncv = (nano_cv *) R_ExternalPtrAddr(cvar);
 
-  return rnng_request_impl(con, data, sendmode, recvmode, timeout, clo, ncv);
+  return rnng_request_impl(con, data, sendmode, recvmode, timeout, clo, ncv, 0);
+
+}
+
+SEXP rnng_request_promise(SEXP con, SEXP data, SEXP cvar, SEXP sendmode, SEXP recvmode, SEXP timeout, SEXP clo) {
+
+  if (R_ExternalPtrTag(con) != nano_ContextSymbol)
+    Rf_error("'con' is not a valid Context");
+
+  nano_cv *ncv = R_ExternalPtrTag(cvar) == nano_CvSymbol ? (nano_cv *) R_ExternalPtrAddr(cvar) : NULL;
+
+  return rnng_request_impl(con, data, sendmode, recvmode, timeout, clo, ncv, 1);
 
 }
 
diff --git a/src/core.c b/src/core.c
index c6723da7b..73d44abcb 100644
--- a/src/core.c
+++ b/src/core.c
@@ -47,7 +47,8 @@ static SEXP eval_safe (void *call) {
 }
 
 static void rl_reset(void *data, Rboolean jump) {
-  if (jump && data == NULL)
+  (void) data;
+  if (jump)
     SET_TAG(nano_refHook, R_NilValue);
 }
 
@@ -982,30 +983,6 @@ SEXP rnng_send(SEXP con, SEXP data, SEXP mode, SEXP block) {
     nng_ctx *ctxp = (nng_ctx *) R_ExternalPtrAddr(con);
     nng_msg *msgp;
 
-#ifdef NANONEXT_LEGACY_NNG
-
-    nng_aio *aiop;
-
-    if ((xc = nng_msg_alloc(&msgp, 0)))
-      goto exitlevel1;
-
-    if ((xc = nng_msg_append(msgp, buf.buf, buf.cur)) ||
-        (xc = nng_aio_alloc(&aiop, NULL, NULL))) {
-      nng_msg_free(msgp);
-      goto exitlevel1;
-    }
-
-    nng_aio_set_msg(aiop, msgp);
-    nng_aio_set_timeout(aiop, flags < 0 ? 0 : flags > 0 ? flags : (*NANO_INTEGER(block) == 1) * NNG_DURATION_DEFAULT);
-    nng_ctx_send(*ctxp, aiop);
-    NANO_FREE(buf);
-    nng_aio_wait(aiop);
-    if ((xc = nng_aio_result(aiop)))
-      nng_msg_free(nng_aio_get_msg(aiop));
-    nng_aio_free(aiop);
-
-#else
-
     if (flags <= 0) {
 
       if ((xc = nng_msg_alloc(&msgp, 0)))
@@ -1043,8 +1020,6 @@ SEXP rnng_send(SEXP con, SEXP data, SEXP mode, SEXP block) {
 
     }
 
-#endif
-
   } else if (ptrtag == nano_StreamSymbol) {
 
     nano_encode(&buf, data);
@@ -1136,30 +1111,6 @@ SEXP rnng_recv(SEXP con, SEXP mode, SEXP block, SEXP bytes) {
     nng_ctx *ctxp = (nng_ctx *) R_ExternalPtrAddr(con);
     nng_msg *msgp;
 
-#ifdef NANONEXT_LEGACY_NNG
-
-    nng_aio *aiop;
-
-    if ((xc = nng_aio_alloc(&aiop, NULL, NULL)))
-      goto exitlevel1;
-    nng_aio_set_timeout(aiop, flags < 0 ? 0 : flags > 0 ? flags : (*NANO_INTEGER(block) == 1) * NNG_DURATION_DEFAULT);
-    nng_ctx_recv(*ctxp, aiop);
-
-    nng_aio_wait(aiop);
-    if ((xc = nng_aio_result(aiop))) {
-      nng_aio_free(aiop);
-      goto exitlevel1;
-    }
-
-    msgp = nng_aio_get_msg(aiop);
-    nng_aio_free(aiop);
-    buf = nng_msg_body(msgp);
-    sz = nng_msg_len(msgp);
-    res = nano_decode(buf, sz, mod);
-    nng_msg_free(msgp);
-
-#else
-
     if (flags <= 0) {
 
       xc = nng_ctx_recvmsg(*ctxp, &msgp, (flags < 0 || *NANO_INTEGER(block) != 1) * NNG_FLAG_NONBLOCK);
@@ -1195,8 +1146,6 @@ SEXP rnng_recv(SEXP con, SEXP mode, SEXP block, SEXP bytes) {
 
     }
 
-#endif
-
   } else if (ptrtag == nano_StreamSymbol) {
 
     mod = nano_matchargs(mode);
diff --git a/src/init.c b/src/init.c
index 9bf9645f0..b2d4c26c0 100644
--- a/src/init.c
+++ b/src/init.c
@@ -50,10 +50,6 @@ SEXP nano_refHook;
 SEXP nano_success;
 SEXP nano_unresolved;
 
-#ifdef NANONEXT_LEGACY_NNG
-nng_mtx *shr_mtx;
-#endif
-
 static void RegisterSymbols(void) {
   nano_AioSymbol = Rf_install("aio");
   nano_ContextSymbol = Rf_install("context");
@@ -158,6 +154,7 @@ static const R_CallMethodDef callMethods[] = {
   {"rnng_recv_aio", (DL_FUNC) &rnng_recv_aio, 5},
   {"rnng_recv_aio_signal", (DL_FUNC) &rnng_recv_aio_signal, 6},
   {"rnng_request", (DL_FUNC) &rnng_request, 6},
+  {"rnng_request_promise", (DL_FUNC) &rnng_request_promise, 7},
   {"rnng_request_signal", (DL_FUNC) &rnng_request_signal, 7},
   {"rnng_send", (DL_FUNC) &rnng_send, 4},
   {"rnng_send_aio", (DL_FUNC) &rnng_send_aio, 5},
@@ -192,9 +189,6 @@ static const R_ExternalMethodDef externalMethods[] = {
 void attribute_visible R_init_nanonext(DllInfo* dll) {
   RegisterSymbols();
   PreserveObjects();
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_alloc(&shr_mtx);
-#endif
   R_registerRoutines(dll, NULL, callMethods, NULL, externalMethods);
   R_useDynamicSymbols(dll, FALSE);
   R_forceSymbols(dll, TRUE);
@@ -202,7 +196,4 @@ void attribute_visible R_init_nanonext(DllInfo* dll) {
 
 void attribute_visible R_unload_nanonext(DllInfo *info) {
   ReleaseObjects();
-#ifdef NANONEXT_LEGACY_NNG
-  nng_mtx_free(shr_mtx);
-#endif
 }
diff --git a/src/later_shim.cpp b/src/later_shim.cpp
new file mode 100644
index 000000000..62e90e173
--- /dev/null
+++ b/src/later_shim.cpp
@@ -0,0 +1,5 @@
+#include <later_api.h>
+
+extern "C" void later2(void (*func)(void*), void* data, double secs) {
+  later::later(func, data, secs);
+}
diff --git a/src/later_shim.h b/src/later_shim.h
new file mode 100644
index 000000000..7a9345b47
--- /dev/null
+++ b/src/later_shim.h
@@ -0,0 +1,7 @@
+#ifndef LATER_SHIM_H
+#define LATER_SHIM_H
+
+// This is simply a shim so that later::later can be accessed from C, not C++
+void later2(void (*func)(void*), void* data, double secs);
+
+#endif
diff --git a/src/nanonext.h b/src/nanonext.h
index 74c43e633..566ac8028 100644
--- a/src/nanonext.h
+++ b/src/nanonext.h
@@ -21,10 +21,6 @@
 
 #include <nng/nng.h>
 
-#if NNG_MAJOR_VERSION == 1 && NNG_MINOR_VERSION < 6
-#define NANONEXT_LEGACY_NNG
-#endif
-
 #ifdef NANONEXT_PROTOCOLS
 #include <nng/protocol/bus0/bus.h>
 #include <nng/protocol/pair0/pair.h>
@@ -45,9 +41,6 @@
 #ifdef NANONEXT_SUPPLEMENTALS
 #include <nng/supplemental/tls/tls.h>
 #include <nng/supplemental/util/platform.h>
-#ifdef NANONEXT_LEGACY_NNG
-extern nng_mtx *shr_mtx;
-#endif
 
 typedef struct nano_listener_s {
   nng_listener list;
@@ -253,6 +246,7 @@ SEXP rnng_recv(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_recv_aio(SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_recv_aio_signal(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_request(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
+SEXP rnng_request_promise(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_request_signal(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send_aio(SEXP, SEXP, SEXP, SEXP, SEXP);