diff --git a/src/pkg.cc b/src/pkg.cc
index 31987a1c..cd94e0d9 100644
--- a/src/pkg.cc
+++ b/src/pkg.cc
@@ -35,10 +35,10 @@
 #include "libsemigroups/blocks.hpp"
 #include "libsemigroups/cong.hpp"
 #include "libsemigroups/froidure-pin.hpp"
-#include "libsemigroups/uf.hpp"
+#include "libsemigroups/uf-old.hpp"
 
 using libsemigroups::Congruence;
-using libsemigroups::detail::UF;
+using libsemigroups::detail::UFOld;
 
 #if !defined(SIZEOF_VOID_P)
 #error Something is wrong with this GAP installation: SIZEOF_VOID_P not defined
@@ -102,7 +102,7 @@ void TSemiObjFreeFunc(Obj o) {
   SEMIGROUPS_ASSERT(TNUM_OBJ(o) == T_SEMI);
   switch (SUBTYPE_OF_T_SEMI(o)) {
     case T_SEMI_SUBTYPE_UF: {
-      delete CLASS_OBJ<UF*>(o);
+      delete CLASS_OBJ<UFOld*>(o);
       break;
     }
     case T_SEMI_SUBTYPE_CONG: {
@@ -157,7 +157,7 @@ void TSemiObjSaveFunc(Obj o) {
 
   switch (SUBTYPE_OF_T_SEMI(o)) {
     case T_SEMI_SUBTYPE_UF: {
-      UF* uf = CLASS_OBJ<UF*>(o);
+      UFOld* uf = CLASS_OBJ<UFOld*>(o);
       SaveUInt(uf->get_size());
       for (size_t i = 0; i < uf->get_size(); i++) {
         SaveUInt(uf->find(i));
@@ -196,7 +196,7 @@ void TSemiObjLoadFunc(Obj o) {
       for (size_t i = 0; i < size; i++) {
         table->push_back(LoadUInt());
       }
-      ADDR_OBJ(o)[1] = reinterpret_cast<Obj>(new UF(*table));
+      ADDR_OBJ(o)[1] = reinterpret_cast<Obj>(new UFOld(*table));
       break;
     }
     case T_SEMI_SUBTYPE_CONG: {
diff --git a/src/uf.cc b/src/uf.cc
index b7fd7c96..7fa34162 100644
--- a/src/uf.cc
+++ b/src/uf.cc
@@ -26,28 +26,28 @@
 #include "semigroups-debug.h"
 #include "src/compiled.h"
 
-#include "libsemigroups/uf.hpp"
+#include "libsemigroups/uf-old.hpp"
 
-using libsemigroups::detail::UF;
+using libsemigroups::detail::UFOld;
 
 // GAP level functions
 
 Obj UF_NEW(Obj self, Obj size) {
   SEMIGROUPS_ASSERT(IS_INTOBJ(size) && INT_INTOBJ(size) > 0);
-  return OBJ_CLASS(new UF(INT_INTOBJ(size)), T_SEMI_SUBTYPE_UF);
+  return OBJ_CLASS(new UFOld(INT_INTOBJ(size)), T_SEMI_SUBTYPE_UF);
 }
 
 Obj UF_COPY(Obj self, Obj uf) {
-  return OBJ_CLASS(new UF(*CLASS_OBJ<UF*>(uf)), T_SEMI_SUBTYPE_UF);
+  return OBJ_CLASS(new UFOld(*CLASS_OBJ<UFOld*>(uf)), T_SEMI_SUBTYPE_UF);
 }
 
 Obj UF_SIZE(Obj self, Obj uf) {
-  return INTOBJ_INT(CLASS_OBJ<UF*>(uf)->get_size());
+  return INTOBJ_INT(CLASS_OBJ<UFOld*>(uf)->get_size());
 }
 
 Obj UF_FIND(Obj self, Obj uf, Obj i) {
   SEMIGROUPS_ASSERT(IS_INTOBJ(i) && INT_INTOBJ(i) > 0);
-  return INTOBJ_INT(CLASS_OBJ<UF*>(uf)->find(INT_INTOBJ(i) - 1) + 1);
+  return INTOBJ_INT(CLASS_OBJ<UFOld*>(uf)->find(INT_INTOBJ(i) - 1) + 1);
 }
 
 Obj UF_UNION(Obj self, Obj uf, Obj pair) {
@@ -56,18 +56,18 @@ Obj UF_UNION(Obj self, Obj uf, Obj pair) {
                     && INT_INTOBJ(ELM_PLIST(pair, 1)) > 0);
   SEMIGROUPS_ASSERT(IS_INTOBJ(ELM_PLIST(pair, 2))
                     && INT_INTOBJ(ELM_PLIST(pair, 2)) > 0);
-  CLASS_OBJ<UF*>(uf)->unite(INT_INTOBJ(ELM_PLIST(pair, 1)) - 1,
+  CLASS_OBJ<UFOld*>(uf)->unite(INT_INTOBJ(ELM_PLIST(pair, 1)) - 1,
                             INT_INTOBJ(ELM_PLIST(pair, 2)) - 1);
   return 0L;
 }
 
 Obj UF_FLATTEN(Obj self, Obj uf) {
-  CLASS_OBJ<UF*>(uf)->flatten();
+  CLASS_OBJ<UFOld*>(uf)->flatten();
   return 0L;
 }
 
 Obj UF_TABLE(Obj self, Obj uf) {
-  UF::table_type* table     = CLASS_OBJ<UF*>(uf)->get_table();
+  UFOld::table_type* table     = CLASS_OBJ<UFOld*>(uf)->get_table();
   size_t          size      = table->size();
   Obj             gap_table = NEW_PLIST_IMM(T_PLIST_CYC, size);
   // IMMUTABLE since it should not be altered on the GAP level
@@ -79,7 +79,7 @@ Obj UF_TABLE(Obj self, Obj uf) {
 }
 
 Obj UF_BLOCKS(Obj self, Obj uf) {
-  UF::blocks_type const* blocks = CLASS_OBJ<UF*>(uf)->get_blocks();
+  UFOld::blocks_type const* blocks = CLASS_OBJ<UFOld*>(uf)->get_blocks();
   size_t                 size   = blocks->size();
   size_t                 i, j;
 
@@ -105,13 +105,13 @@ Obj UF_BLOCKS(Obj self, Obj uf) {
 gap_int_t UF_NR_BLOCKS(Obj self, Obj uf) {
   SEMIGROUPS_ASSERT(TNUM_OBJ(uf) == T_SEMI
                     && SUBTYPE_OF_T_SEMI(uf) == T_SEMI_SUBTYPE_UF);
-  return INTOBJ_INT(CLASS_OBJ<UF*>(uf)->nr_blocks());
+  return INTOBJ_INT(CLASS_OBJ<UFOld*>(uf)->nr_blocks());
 }
 
 gap_list_t UF_BLOCK_REPS(Obj self, Obj uf) {
   SEMIGROUPS_ASSERT(TNUM_OBJ(uf) == T_SEMI
                     && SUBTYPE_OF_T_SEMI(uf) == T_SEMI_SUBTYPE_UF);
-  UF* uf_cpp = CLASS_OBJ<UF*>(uf);
+  UFOld* uf_cpp = CLASS_OBJ<UFOld*>(uf);
   uf_cpp->reset_next_rep();
   size_t next_rep = uf_cpp->next_rep();
 
@@ -132,8 +132,8 @@ Obj UF_JOIN(Obj self, Obj uf1, Obj uf2) {
   SEMIGROUPS_ASSERT(TNUM_OBJ(uf2) == T_SEMI
                     && SUBTYPE_OF_T_SEMI(uf2) == T_SEMI_SUBTYPE_UF);
   SEMIGROUPS_ASSERT(CLASS_OBJ<UF*>(uf1)->get_size()
-                    == CLASS_OBJ<UF*>(uf2)->get_size());
+                    == CLASS_OBJ<UFOld*>(uf2)->get_size());
   Obj uf_join = UF_COPY(self, uf1);
-  CLASS_OBJ<UF*>(uf_join)->join(CLASS_OBJ<UF*>(uf2));
+  CLASS_OBJ<UFOld*>(uf_join)->join(CLASS_OBJ<UFOld*>(uf2));
   return uf_join;
 }