diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5eed169..9cf6803 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.18)
 project(tentris
-        VERSION 1.3.0
+        VERSION 1.3.1
         DESCRIPTION "tensor-based triplestore")
 
 include(cmake/boilerplate_init.cmake)
diff --git a/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.cpp b/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.cpp
index 476da61..aa3f42b 100644
--- a/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.cpp
+++ b/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.cpp
@@ -24,7 +24,7 @@ namespace dice::sparql2tensor {
 		SPARQLQuery p_sparql{};
 		if (q_ctx->prologue()) {
 			parser::visitors::PrologueVisitor p_visitor{};
-			p_sparql.prefixes_ = std::any_cast<robin_hood::unordered_map<std::string, std::string>>(p_visitor.visitPrologue(q_ctx->prologue()));
+			p_sparql.prefixes_ = std::any_cast<rdf4cpp::rdf::parser::IStreamQuadIterator::prefix_storage_type>(p_visitor.visitPrologue(q_ctx->prologue()));
 		}
 
 		parser::visitors::SelectAskQueryVisitor visitor{&p_sparql};
diff --git a/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.hpp b/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.hpp
index ea4f946..52c0a1d 100644
--- a/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.hpp
+++ b/libs/sparql2tensor/src/dice/sparql2tensor/SPARQLQuery.hpp
@@ -21,7 +21,7 @@ namespace dice::sparql2tensor {
 
 		std::vector<rdf4cpp::rdf::query::TriplePattern> triple_patterns_;
 
-		robin_hood::unordered_map<std::string, std::string> prefixes_;
+		rdf4cpp::rdf::parser::IStreamQuadIterator::prefix_storage_type prefixes_;
 
 		bool distinct_ = false;