diff --git a/.ci/pipelines/acceptance.groovy b/.ci/pipelines/acceptance.groovy
index babc91f77..cf8923e2f 100644
--- a/.ci/pipelines/acceptance.groovy
+++ b/.ci/pipelines/acceptance.groovy
@@ -11,7 +11,7 @@ pipeline {
         axes {
           axis {
             name 'ES_VERSION'
-            values '8.0.0', '7.15.1'
+            values '7.11.2', '7.12.1', '7.13.4', '7.14.2', '7.15.2', '7.16.3', '7.17.4', '8.0.1', '8.1.3', '8.2.2'
           }
         }
         agent { label('linux && immutable && docker') }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index eec8d1858..6dc63f0a0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## [Unreleased]
 ### Fixed
 - Correctly identify a missing security user ([#101](https://github.com/elastic/terraform-provider-elasticstack/issues/101))
+- Support **7.x** Elasticsearch < **7.15** by removing the default `media_type` attribute in the Append processor ([#118](https://github.com/elastic/terraform-provider-elasticstack/pull/118))
 
 ## [0.3.3] - 2023-03-22
 ### Fixed
diff --git a/docs/data-sources/elasticsearch_ingest_processor_append.md b/docs/data-sources/elasticsearch_ingest_processor_append.md
index c0ff6bbb5..c556abed8 100644
--- a/docs/data-sources/elasticsearch_ingest_processor_append.md
+++ b/docs/data-sources/elasticsearch_ingest_processor_append.md
@@ -48,7 +48,7 @@ resource "elasticstack_elasticsearch_ingest_pipeline" "my_ingest_pipeline" {
 - **description** (String) Description of the processor.
 - **if** (String) Conditionally execute the processor
 - **ignore_failure** (Boolean) Ignore failures for the processor.
-- **media_type** (String) The media type for encoding value. Applies only when value is a template snippet. Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.
+- **media_type** (String) The media type for encoding value. Applies only when value is a template snippet. Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`. Supported only from Elasticsearch version **7.15**.
 - **on_failure** (List of String) Handle failures for the processor.
 - **tag** (String) Identifier for the processor.
 
diff --git a/internal/elasticsearch/ingest/processor_append_data_source.go b/internal/elasticsearch/ingest/processor_append_data_source.go
index 1dad6cad5..0a2128d41 100644
--- a/internal/elasticsearch/ingest/processor_append_data_source.go
+++ b/internal/elasticsearch/ingest/processor_append_data_source.go
@@ -40,10 +40,9 @@ func DataSourceProcessorAppend() *schema.Resource {
 			Default:     true,
 		},
 		"media_type": {
-			Description: "The media type for encoding value. Applies only when value is a template snippet. Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`.",
+			Description: "The media type for encoding value. Applies only when value is a template snippet. Must be one of `application/json`, `text/plain`, or `application/x-www-form-urlencoded`. Supported only from Elasticsearch version **7.15**.",
 			Type:        schema.TypeString,
 			Optional:    true,
-			Default:     "application/json",
 		},
 		"description": {
 			Description: "Description of the processor. ",
diff --git a/internal/elasticsearch/ingest/processor_append_data_source_test.go b/internal/elasticsearch/ingest/processor_append_data_source_test.go
index 3a84ca80a..52d9a1eca 100644
--- a/internal/elasticsearch/ingest/processor_append_data_source_test.go
+++ b/internal/elasticsearch/ingest/processor_append_data_source_test.go
@@ -27,8 +27,7 @@ const expectedJsonAppend = `{
 	"append": {
 		"field": "tags", 
 		"value": ["production", "{{{app}}}", "{{{owner}}}"], 
-		"allow_duplicates": true, 
-		"media_type": "application/json", 
+		"allow_duplicates": true,
 		"description": "Append tags to the doc", 
 		"ignore_failure": false
 	}
diff --git a/internal/models/ingest.go b/internal/models/ingest.go
index f11e8616d..0c70aa3b1 100644
--- a/internal/models/ingest.go
+++ b/internal/models/ingest.go
@@ -28,7 +28,7 @@ type ProcessorAppend struct {
 	Field           string   `json:"field"`
 	Value           []string `json:"value"`
 	AllowDuplicates bool     `json:"allow_duplicates"`
-	MediaType       string   `json:"media_type"`
+	MediaType       string   `json:"media_type,omitempty"`
 }
 
 type ProcessorBytes struct {