diff --git a/src/parser/c11.yy b/src/parser/c11.yy
index d89e1ad241..858b7d734a 100644
--- a/src/parser/c11.yy
+++ b/src/parser/c11.yy
@@ -49,7 +49,7 @@
 %define api.namespace {nmodl::parser}
 
 /** set the parser's class identifier */
-%define parser_class_name {CParser}
+%define api.parser.class {CParser}
 
 /** keep track of the current position within the input */
 %locations
diff --git a/src/parser/diffeq.yy b/src/parser/diffeq.yy
index 60fad8a7a8..b330ccb227 100644
--- a/src/parser/diffeq.yy
+++ b/src/parser/diffeq.yy
@@ -53,7 +53,7 @@
 %define api.namespace {nmodl::parser}
 
 /** set the parser's class identifier */
-%define parser_class_name {DiffeqParser}
+%define api.parser.class {DiffeqParser}
 
 /** keep track of the current position within the input */
 %locations
diff --git a/src/parser/nmodl.yy b/src/parser/nmodl.yy
index c07bd961a3..13ae3e80e3 100644
--- a/src/parser/nmodl.yy
+++ b/src/parser/nmodl.yy
@@ -61,7 +61,7 @@
 %define api.namespace {nmodl::parser}
 
 /** set the parser's class identifier */
-%define parser_class_name {NmodlParser}
+%define api.parser.class {NmodlParser}
 
 /** keep track of the current position within the input */
 %locations
diff --git a/src/parser/unit.yy b/src/parser/unit.yy
index 03ebf31ed2..8755bffa91 100644
--- a/src/parser/unit.yy
+++ b/src/parser/unit.yy
@@ -46,7 +46,7 @@
 %define api.namespace {nmodl::parser}
 
 /** set the parser's class identifier */
-%define parser_class_name {UnitParser}
+%define api.parser.class {UnitParser}
 
 /** keep track of the current position within the input */
 %locations