diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
index 1e24fc3ad52..dc8cc74432b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
@@ -17,6 +17,10 @@
 
 package org.openapitools.codegen.languages;
 
+import com.samskivert.mustache.Mustache.Lambda;
+import com.samskivert.mustache.Mustache;
+import com.samskivert.mustache.Template;
+
 import io.swagger.v3.oas.models.examples.Example;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
@@ -33,6 +37,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.Writer;
 import java.util.*;
 import java.util.regex.Pattern;
 
@@ -232,6 +238,17 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
         supportingFiles.add(new SupportingFile("api_client.mustache", File.separator + "R", "api_client.R"));
         supportingFiles.add(new SupportingFile("NAMESPACE.mustache", "", "NAMESPACE"));
         supportingFiles.add(new SupportingFile("testthat.mustache", File.separator + "tests", "testthat.R"));
+
+        // add lambda for mustache templates to fix license field
+        additionalProperties.put("lambdaLicense", new Mustache.Lambda() {
+            @Override
+            public void execute(Template.Fragment fragment, Writer writer) throws IOException {
+                String content = fragment.execute();
+                content = content.trim().replace("Apache-2.0", "Apache License 2.0");
+                writer.write(content);
+            }
+        });
+
     }
 
     @Override
diff --git a/modules/openapi-generator/src/main/resources/r/description.mustache b/modules/openapi-generator/src/main/resources/r/description.mustache
index d3ca9069c5f..2bafa3c15fe 100644
--- a/modules/openapi-generator/src/main/resources/r/description.mustache
+++ b/modules/openapi-generator/src/main/resources/r/description.mustache
@@ -1,13 +1,14 @@
 Package: {{{packageName}}}
 Title: R Package Client for {{{appName}}}
 Version: {{packageVersion}}
-Authors@R: person("{{infoName}}{{^infoName}}OpenAPI Generator community{{/infoName}}", email = "{{infoEmail}}{{^infoEmail}}team@openapitools.org{{/infoEmail}}", role = c("aut", "cre"))
+Author: person("{{infoName}}{{^infoName}}OpenAPI Generator community{{/infoName}}", email = "{{infoEmail}}{{^infoEmail}}team@openapitools.org{{/infoEmail}}", role = c("aut", "cre"))
+Maintainer: {{infoName}}{{^infoName}}OpenAPI Generator community{{/infoName}} <{{infoEmail}}{{^infoEmail}}team@openapitools.org{{/infoEmail}}>
 Description: {{{appDescription}}}{{^appDescription}}R Package Client for {{{appName}}}{{/appDescription}}
 URL: https://{{{gitHost}}}/{{{gitUserId}}}/{{{gitRepoId}}}
 BugReports: https://{{{gitHost}}}/{{{gitUserId}}}/{{{gitRepoId}}}/issues
 Depends: R (>= 3.3)
 Encoding: UTF-8
-License: {{licenseInfo}}{{^licenseInfo}}Unlicense{{/licenseInfo}}
+License: {{#lambdaLicense}}{{licenseInfo}}{{/lambdaLicense}}{{^licenseInfo}}Unlicense{{/licenseInfo}}
 LazyData: true
 Suggests: testthat
 Imports: jsonlite, httr, R6, base64enc{{#useRlangExceptionHandling}}, rlang{{/useRlangExceptionHandling}}
diff --git a/modules/openapi-generator/src/main/resources/r/testthat.mustache b/modules/openapi-generator/src/main/resources/r/testthat.mustache
index 613dc9c4152..c6770a46d18 100644
--- a/modules/openapi-generator/src/main/resources/r/testthat.mustache
+++ b/modules/openapi-generator/src/main/resources/r/testthat.mustache
@@ -1,5 +1,4 @@
 library(testthat)
-library(rjson)
 library({{{packageName}}})
 
 test_check("{{{packageName}}}")
diff --git a/samples/client/petstore/R/DESCRIPTION b/samples/client/petstore/R/DESCRIPTION
index 985a6e7b131..6293ab707f3 100644
--- a/samples/client/petstore/R/DESCRIPTION
+++ b/samples/client/petstore/R/DESCRIPTION
@@ -1,13 +1,14 @@
 Package: petstore
 Title: R Package Client for OpenAPI Petstore
 Version: 1.0.0
-Authors@R: person("OpenAPI Generator community", email = "team@openapitools.org", role = c("aut", "cre"))
+Author: person("OpenAPI Generator community", email = "team@openapitools.org", role = c("aut", "cre"))
+Maintainer: OpenAPI Generator community <team@openapitools.org>
 Description: This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
 URL: https://github.com/GIT_USER_ID/GIT_REPO_ID
 BugReports: https://github.com/GIT_USER_ID/GIT_REPO_ID/issues
 Depends: R (>= 3.3)
 Encoding: UTF-8
-License: Apache-2.0
+License: Apache License 2.0
 LazyData: true
 Suggests: testthat
 Imports: jsonlite, httr, R6, base64enc
diff --git a/samples/client/petstore/R/tests/testthat.R b/samples/client/petstore/R/tests/testthat.R
index e27ee491ed1..d67bd9cf238 100644
--- a/samples/client/petstore/R/tests/testthat.R
+++ b/samples/client/petstore/R/tests/testthat.R
@@ -1,5 +1,4 @@
 library(testthat)
-library(rjson)
 library(petstore)
 
 test_check("petstore")
diff --git a/samples/client/petstore/R/tests/testthat/test_petstore.R b/samples/client/petstore/R/tests/testthat/test_petstore.R
index 4fed54b44ab..6e7cde566e1 100644
--- a/samples/client/petstore/R/tests/testthat/test_petstore.R
+++ b/samples/client/petstore/R/tests/testthat/test_petstore.R
@@ -94,7 +94,7 @@ test_that("GetPetById", {
 test_that("GetPetById with data_file", {
   # test to ensure json is saved to the file `get_pet_by_id.json`
   petResponse <- petApi$GetPetById(petId, data_file="get_pet_by_id.json")
-  response <- fromJSON(file = "get_pet_by_id.json")
+  response <- read_json("get_pet_by_id.json")
   expect_true(!is.null(response))
   expect_equal(response$id, petId)
   expect_equal(response$name, "name_test")