diff --git a/README.adoc b/README.adoc
index a2f6e60..5c2065c 100644
--- a/README.adoc
+++ b/README.adoc
@@ -21,7 +21,7 @@ support Atom at the moment.
 === Dependencies
 
 * Tested OS: Linux
-* C++ compiler (tested: link:{uri-gcc}[gcc] 7/9)
+* C++ compiler (tested: link:{uri-gcc}[gcc] 7/8/9)
 * link:{uri-cmake}[cmake] (at least: 3.9)
 * link:{uri-boost}[boost] (at least: 1.62)
 * link:{uri-mastodon-cpp}[mastodon-cpp] (at least: 0.111.3)
diff --git a/src/config.cpp b/src/config.cpp
index f617a89..a2d9e35 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -257,7 +257,8 @@ void Config::write()
     _json[_profile]["instance"] = data.instance;
     _json[_profile]["interval"] = data.interval;
     _json[_profile]["last_guid"] = data.last_guid;
-    _json[_profile]["max_size"] = data.max_size;
+    _json[_profile]["max_size"]
+        = static_cast<Json::Value::UInt64>(data.max_size);
     // Leave skip.
     _json[_profile]["titles_as_cw"] = data.titles_as_cw;
     _json[_profile]["titles_only"] = data.titles_only;