diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d7560b1d..a8c6a849e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,12 @@ All notable changes to this project will be documented in this file.
 
 This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 7.7.0 Release
+
+### Breaking
+- General
+  - When using `returnIdOnly` parameter; the ids returned now use 'string' rather than 'number' JSON data type, to avoid rounding. Fixes #367.
+  
 ## 7.6.0 Release (Jan 2022)
 Minor release with bug fixes and improvements.
 
@@ -28,7 +34,6 @@ Minor release with bug fixes and improvements.
  - Authoring
    - MAINT-1842 Fix false warnings when using semantic tag pattern.
 
-
 ## 7.5.4 Release (Dec 2021)
 Maintenance release with new features in FHIR and many improvements and fixes.
 
diff --git a/src/main/java/org/snomed/snowstorm/rest/ConceptController.java b/src/main/java/org/snomed/snowstorm/rest/ConceptController.java
index d37c29b45..ca319f36d 100644
--- a/src/main/java/org/snomed/snowstorm/rest/ConceptController.java
+++ b/src/main/java/org/snomed/snowstorm/rest/ConceptController.java
@@ -23,6 +23,8 @@
 import org.snomed.snowstorm.core.pojo.BranchTimepoint;
 import org.snomed.snowstorm.core.pojo.LanguageDialect;
 import org.snomed.snowstorm.core.util.PageHelper;
+import org.snomed.snowstorm.core.util.SearchAfterPage;
+import org.snomed.snowstorm.core.util.SearchAfterPageImpl;
 import org.snomed.snowstorm.core.util.TimerUtil;
 import org.snomed.snowstorm.ecl.validation.ECLValidator;
 import org.snomed.snowstorm.rest.converter.SearchAfterHelper;
@@ -46,6 +48,7 @@
 
 import javax.validation.Valid;
 import java.util.*;
+import java.util.stream.Collectors;
 
 import static io.kaicode.elasticvc.api.ComponentService.LARGE_PAGE;
 import static org.apache.commons.lang3.StringUtils.isNotBlank;
@@ -181,7 +184,10 @@ public ItemsPage<?> findConcepts(
 			pageRequest = getPageRequestWithSort(offset, limit, searchAfter, Sort.sort(QueryConcept.class).by(QueryConcept::getConceptIdL).descending());
 		}
 		if (returnIdOnly) {
-			return new ItemsPage<>(queryService.searchForIds(queryBuilder, branch, pageRequest));
+			SearchAfterPage<Long> longsPage = queryService.searchForIds(queryBuilder, branch, pageRequest);
+			SearchAfterPageImpl<String> stringPage = new SearchAfterPageImpl<>(longsPage.stream().map(Object::toString).collect(Collectors.toList()),
+					longsPage.getPageable(), longsPage.getTotalElements(), longsPage.getSearchAfter());
+			return new ItemsPage<>(stringPage);
 		} else {
 			return new ItemsPage<>(queryService.search(queryBuilder, branch, pageRequest));
 		}