diff --git a/skeletons/OPEN_TYPE.c b/skeletons/OPEN_TYPE.c
index 8886f0a02..396a568a9 100644
--- a/skeletons/OPEN_TYPE.c
+++ b/skeletons/OPEN_TYPE.c
@@ -400,5 +400,117 @@ OPEN_TYPE_encode_uper(const asn_TYPE_descriptor_t *td,
     ASN__ENCODED_OK(er);
 }
 
+asn_dec_rval_t
+OPEN_TYPE_aper_get(const asn_codec_ctx_t *opt_codec_ctx,
+                   const asn_TYPE_descriptor_t *td, void *sptr,
+                   const asn_TYPE_member_t *elm, asn_per_data_t *pd) {
+    asn_type_selector_result_t selected;
+    void *memb_ptr;   /* Pointer to the member */
+    void **memb_ptr2; /* Pointer to that pointer */
+    void *inner_value;
+    asn_dec_rval_t rv;
+
+    if(!(elm->flags & ATF_OPEN_TYPE)) {
+        ASN__DECODE_FAILED;
+    }
+
+    if(!elm->type_selector) {
+        ASN_DEBUG("Type selector is not defined for Open Type %s->%s->%s",
+                  td->name, elm->name, elm->type->name);
+        ASN__DECODE_FAILED;
+    }
+
+    selected = elm->type_selector(td, sptr);
+    if(!selected.presence_index) {
+        ASN__DECODE_FAILED;
+    }
+
+    /* Fetch the pointer to this member */
+    assert(elm->flags == ATF_OPEN_TYPE);
+    if(elm->flags & ATF_POINTER) {
+        memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
+    } else {
+        memb_ptr = (char *)sptr + elm->memb_offset;
+        memb_ptr2 = &memb_ptr;
+    }
+    if(*memb_ptr2 != NULL) {
+        /* Make sure we reset the structure first before encoding */
+        if(CHOICE_variant_set_presence(elm->type, *memb_ptr2, 0)
+           != 0) {
+            ASN__DECODE_FAILED;
+        }
+    }
+
+    inner_value =
+        (char *)*memb_ptr2
+        + elm->type->elements[selected.presence_index - 1].memb_offset;
+
+    rv = aper_open_type_get(opt_codec_ctx, selected.type_descriptor, NULL,
+                            &inner_value, pd);
+    switch(rv.code) {
+    case RC_OK:
+        if(CHOICE_variant_set_presence(elm->type, *memb_ptr2,
+                                       selected.presence_index)
+           == 0) {
+            break;
+        } else {
+            rv.code = RC_FAIL;
+        }
+        /* Fall through */
+    case RC_WMORE:
+    case RC_FAIL:
+        if(*memb_ptr2) {
+            const asn_CHOICE_specifics_t *specs =
+                selected.type_descriptor->specifics;
+            if(elm->flags & ATF_POINTER) {
+                ASN_STRUCT_FREE(*selected.type_descriptor, inner_value);
+                *memb_ptr2 = NULL;
+            } else {
+                ASN_STRUCT_FREE_CONTENTS_ONLY(*selected.type_descriptor,
+                                              inner_value);
+                memset(*memb_ptr2, 0, specs->struct_size);
+            }
+        }
+    }
+    return rv;
+}
+
+asn_enc_rval_t
+OPEN_TYPE_encode_aper(const asn_TYPE_descriptor_t *td,
+                      const asn_per_constraints_t *constraints,
+                      const void *sptr, asn_per_outp_t *po) {
+    const void *memb_ptr;   /* Pointer to the member */
+    asn_TYPE_member_t *elm; /* CHOICE's element */
+    asn_enc_rval_t er;
+    unsigned present;
+
+    (void)constraints;
+
+    present = CHOICE_variant_get_presence(td, sptr);
+    if(present == 0 || present > td->elements_count) {
+        ASN__ENCODE_FAILED;
+    } else {
+        present--;
+    }
+
+    ASN_DEBUG("Encoding %s OPEN TYPE element %d", td->name, present);
+
+    elm = &td->elements[present];
+    if(elm->flags & ATF_POINTER) {
+        /* Member is a pointer to another structure */
+        memb_ptr =
+            *(const void *const *)((const char *)sptr + elm->memb_offset);
+        if(!memb_ptr) ASN__ENCODE_FAILED;
+    } else {
+        memb_ptr = (const char *)sptr + elm->memb_offset;
+    }
+
+    if(aper_open_type_put(elm->type, NULL, memb_ptr, po) < 0) {
+        ASN__ENCODE_FAILED;
+    }
+
+    er.encoded = 0;
+    ASN__ENCODED_OK(er);
+}
 
 #endif  /* ASN_DISABLE_PER_SUPPORT */
diff --git a/skeletons/OPEN_TYPE.h b/skeletons/OPEN_TYPE.h
index 4312e6023..1c091f14f 100644
--- a/skeletons/OPEN_TYPE.h
+++ b/skeletons/OPEN_TYPE.h
@@ -21,7 +21,6 @@ extern "C" {
 #define OPEN_TYPE_encode_xer CHOICE_encode_xer
 #define OPEN_TYPE_decode_uper NULL
 #define OPEN_TYPE_decode_aper NULL
-#define OPEN_TYPE_encode_aper CHOICE_encode_aper
 
 extern asn_TYPE_operation_t asn_OP_OPEN_TYPE;
 
@@ -53,11 +52,22 @@ asn_dec_rval_t OPEN_TYPE_uper_get(const asn_codec_ctx_t *opt_codec_ctx,
                                   const asn_TYPE_member_t *element,
                                   asn_per_data_t *pd);
 
+asn_dec_rval_t OPEN_TYPE_aper_get(const asn_codec_ctx_t *opt_codec_ctx,
+                                  const asn_TYPE_descriptor_t *parent_type,
+                                  void *parent_structure,
+                                  const asn_TYPE_member_t *element,
+                                  asn_per_data_t *pd);
+
 asn_enc_rval_t OPEN_TYPE_encode_uper(
     const asn_TYPE_descriptor_t *type_descriptor,
     const asn_per_constraints_t *constraints, const void *struct_ptr,
     asn_per_outp_t *per_output);
 
+asn_enc_rval_t OPEN_TYPE_encode_aper(
+    const asn_TYPE_descriptor_t *type_descriptor,
+    const asn_per_constraints_t *constraints, const void *struct_ptr,
+    asn_per_outp_t *per_output);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/skeletons/asn_application.c b/skeletons/asn_application.c
index ee74e32fc..fb2a7d416 100644
--- a/skeletons/asn_application.c
+++ b/skeletons/asn_application.c
@@ -239,6 +239,8 @@ asn_encode_internal(const asn_codec_ctx_t *opt_codec_ctx,
 #ifdef  ASN_DISABLE_PER_SUPPORT
     case ATS_UNALIGNED_BASIC_PER:
     case ATS_UNALIGNED_CANONICAL_PER:
+    case ATS_ALIGNED_BASIC_PER:
+    case ATS_ALIGNED_CANONICAL_PER:
         errno = ENOENT; /* PER is not defined. */
         ASN__ENCODE_FAILED;
         break;
@@ -273,6 +275,36 @@ asn_encode_internal(const asn_codec_ctx_t *opt_codec_ctx,
             ASN__ENCODE_FAILED;
         }
         break;
+    case ATS_ALIGNED_BASIC_PER:
+        /* CANONICAL-APER is a superset of BASIC-APER. */
+        /* Fall through. */
+    case ATS_ALIGNED_CANONICAL_PER:
+        if(td->op->aper_encoder) {
+            er = aper_encode(td, 0, sptr, callback, callback_key);
+            if(er.encoded == -1) {
+                if(er.failed_type && er.failed_type->op->aper_encoder) {
+                    errno = EBADF;  /* Structure has incorrect form. */
+                } else {
+                    errno = ENOENT; /* APER is not defined for this type. */
+                }
+            } else {
+                ASN_DEBUG("Complete encoded in %ld bits", (long)er.encoded);
+                if(er.encoded == 0) {
+                    /* Enforce "Complete Encoding" of X.691 #11.1 */
+                    if(callback("\0", 1, callback_key) < 0) {
+                        errno = EBADF;
+                        ASN__ENCODE_FAILED;
+                    }
+                    er.encoded = 8; /* Exactly 8 zero bits is added. */
+                }
+                /* Convert bits into bytes */
+                er.encoded = (er.encoded + 7) >> 3;
+            }
+        } else {
+            errno = ENOENT; /* Transfer syntax is not defined for this type. */
+            ASN__ENCODE_FAILED;
+        }
+        break;
 #endif  /* ASN_DISABLE_PER_SUPPORT */
 
     case ATS_BASIC_XER:
diff --git a/skeletons/constr_SEQUENCE.c b/skeletons/constr_SEQUENCE.c
index b68d1f29e..7e35cbffa 100644
--- a/skeletons/constr_SEQUENCE.c
+++ b/skeletons/constr_SEQUENCE.c
@@ -1594,9 +1594,14 @@ SEQUENCE_decode_aper(const asn_codec_ctx_t *opt_codec_ctx,
 		}
 
 		/* Fetch the member from the stream */
-		ASN_DEBUG("Decoding member %s in %s", elm->name, td->name);
-		rv = elm->type->op->aper_decoder(opt_codec_ctx, elm->type,
-		                                 elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+		ASN_DEBUG("Decoding member \"%s\" in %s", elm->name, td->name);
+
+		if(elm->flags & ATF_OPEN_TYPE) {
+			rv = OPEN_TYPE_aper_get(opt_codec_ctx, td, st, elm, pd);
+		} else {
+			rv = elm->type->op->aper_decoder(opt_codec_ctx, elm->type,
+					elm->encoding_constraints.per_constraints, memb_ptr2, pd);
+		}
 		if(rv.code != RC_OK) {
 			ASN_DEBUG("Failed decode %s in %s",
 			          elm->name, td->name);
diff --git a/skeletons/per_decoder.c b/skeletons/per_decoder.c
index 63781b254..8a3e39df8 100644
--- a/skeletons/per_decoder.c
+++ b/skeletons/per_decoder.c
@@ -96,7 +96,9 @@ uper_decode(const asn_codec_ctx_t *opt_codec_ctx,
 }
 
 asn_dec_rval_t
-aper_decode_complete(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size) {
+aper_decode_complete(const asn_codec_ctx_t *opt_codec_ctx,
+                     const asn_TYPE_descriptor_t *td, void **sptr,
+                     const void *buffer, size_t size) {
 	asn_dec_rval_t rval;
 
 	rval = aper_decode(opt_codec_ctx, td, sptr, buffer, size, 0, 0);
@@ -125,7 +127,9 @@ aper_decode_complete(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
 }
 
 asn_dec_rval_t
-aper_decode(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td, void **sptr, const void *buffer, size_t size, int skip_bits, int unused_bits) {
+aper_decode(const asn_codec_ctx_t *opt_codec_ctx,
+            const asn_TYPE_descriptor_t *td, void **sptr, const void *buffer,
+            size_t size, int skip_bits, int unused_bits) {
 	asn_codec_ctx_t s_codec_ctx;
 	asn_dec_rval_t rval;
 	asn_per_data_t pd;
diff --git a/skeletons/per_decoder.h b/skeletons/per_decoder.h
index c28e1e2f4..5cbe27911 100644
--- a/skeletons/per_decoder.h
+++ b/skeletons/per_decoder.h
@@ -44,8 +44,9 @@ asn_dec_rval_t uper_decode(
  * Aligned PER decoder of a "complete encoding" as per X.691#10.1.
  * On success, this call always returns (.consumed >= 1), in BITS, as per X.691#10.1.3.
  */
-asn_dec_rval_t aper_decode_complete(struct asn_codec_ctx_s *opt_codec_ctx,
-       struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+asn_dec_rval_t aper_decode_complete(
+       const struct asn_codec_ctx_s *opt_codec_ctx,
+       const struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
        void **struct_ptr,	/* Pointer to a target structure's pointer */
        const void *buffer,	/* Data to be decoded */
        size_t size		/* Size of data buffer */
@@ -55,8 +56,9 @@ asn_dec_rval_t aper_decode_complete(struct asn_codec_ctx_s *opt_codec_ctx,
  * Aligned PER decoder of any ASN.1 type. May be invoked by the application.
  * WARNING: This call returns the number of BITS read from the stream. Beware.
  */
-asn_dec_rval_t aper_decode(struct asn_codec_ctx_s *opt_codec_ctx,
-      struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+asn_dec_rval_t aper_decode(
+      const struct asn_codec_ctx_s *opt_codec_ctx,
+      const struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
       void **struct_ptr,	/* Pointer to a target structure's pointer */
       const void *buffer,	/* Data to be decoded */
       size_t size,		/* Size of data buffer */
diff --git a/skeletons/per_encoder.c b/skeletons/per_encoder.c
index 642f1e249..5680aaabd 100644
--- a/skeletons/per_encoder.c
+++ b/skeletons/per_encoder.c
@@ -155,57 +155,34 @@ _uper_encode_flush_outp(asn_per_outp_t *po) {
 	return po->output(po->tmpspace, buf - po->tmpspace, po->op_key);
 }
 
-static asn_enc_rval_t aper_encode_internal(const asn_TYPE_descriptor_t *td,
-        const asn_per_constraints_t *,
-        const void *sptr, asn_app_consume_bytes_f *cb, void *app_key);
-
-asn_enc_rval_t
-aper_encode(const asn_TYPE_descriptor_t *td,
-            const void *sptr, asn_app_consume_bytes_f *cb, void *app_key) {
-       return aper_encode_internal(td, 0, sptr, cb, app_key);
-}
-
-asn_enc_rval_t
-aper_encode_to_buffer(const asn_TYPE_descriptor_t *td,
-        const void *sptr, void *buffer, size_t buffer_size) {
-	enc_to_buf_arg key;
-
-	key.buffer = buffer;
-	key.left = buffer_size;
-
-	if(td) ASN_DEBUG("Encoding \"%s\" using ALIGNED PER", td->name);
-
-	return aper_encode_internal(td, 0, sptr, encode_to_buffer_cb, &key);
-}
-
 ssize_t
 aper_encode_to_new_buffer(const asn_TYPE_descriptor_t *td,
-        const asn_per_constraints_t *constraints,
-        const void *sptr, void **buffer_r) {
-	asn_enc_rval_t er;
+                          const asn_per_constraints_t *constraints,
+                          const void *sptr, void **buffer_r) {
+    asn_enc_rval_t er;
 	enc_dyn_arg key;
 
 	memset(&key, 0, sizeof(key));
 
-	er = aper_encode_internal(td, constraints, sptr, encode_dyn_cb, &key);
+	er = aper_encode(td, constraints, sptr, encode_dyn_cb, &key);
 	switch(er.encoded) {
-		case -1:
-			FREEMEM(key.buffer);
-			return -1;
-		case 0:
-			FREEMEM(key.buffer);
-			key.buffer = MALLOC(1);
-			if(key.buffer) {
-				*(char *)key.buffer = '\0';
-				*buffer_r = key.buffer;
-				return 1;
-			} else {
-				return -1;
-			}
-		default:
+	case -1:
+		FREEMEM(key.buffer);
+		return -1;
+	case 0:
+		FREEMEM(key.buffer);
+		key.buffer = MALLOC(1);
+		if(key.buffer) {
+			*(char *)key.buffer = '\0';
 			*buffer_r = key.buffer;
-			ASN_DEBUG("Complete encoded in %ld bits", er.encoded);
-			return ((er.encoded + 7) >> 3);
+			return 1;
+		} else {
+			return -1;
+		}
+	default:
+		*buffer_r = key.buffer;
+		ASN_DEBUG("Complete encoded in %ld bits", (long)er.encoded);
+		return ((er.encoded + 7) >> 3);
 	}
 }
 
@@ -229,8 +206,8 @@ _aper_encode_flush_outp(asn_per_outp_t *po) {
 	return 0;
 }
 
-static asn_enc_rval_t
-aper_encode_internal(const asn_TYPE_descriptor_t *td,
+asn_enc_rval_t
+aper_encode(const asn_TYPE_descriptor_t *td,
         const asn_per_constraints_t *constraints,
         const void *sptr, asn_app_consume_bytes_f *cb, void *app_key) {
 	asn_per_outp_t po;
diff --git a/skeletons/per_encoder.h b/skeletons/per_encoder.h
index 26be3fe58..b615ef028 100644
--- a/skeletons/per_encoder.h
+++ b/skeletons/per_encoder.h
@@ -30,6 +30,7 @@ asn_enc_rval_t uper_encode(
 
 asn_enc_rval_t aper_encode(
     const struct asn_TYPE_descriptor_s *type_descriptor,
+    const asn_per_constraints_t *constraints,
     const void *struct_ptr,                     /* Structure to be encoded */
     asn_app_consume_bytes_f *consume_bytes_cb,  /* Data collector */
     void *app_key                               /* Arbitrary callback argument */
@@ -50,6 +51,7 @@ asn_enc_rval_t uper_encode_to_buffer(
 
 asn_enc_rval_t aper_encode_to_buffer(
     const struct asn_TYPE_descriptor_s *type_descriptor,
+    const asn_per_constraints_t *constraints,
     const void *struct_ptr,  /* Structure to be encoded */
     void *buffer,            /* Pre-allocated buffer */
     size_t buffer_size       /* Initial buffer size (max) */