C/igraph 0.8.3 is now released. As usual, the source code can be obtained from the GitHub releases page.
The summary of changes is below.
Added

igraph_vector_binsearch_slice()
performs binary search on a sorted slice of a vector.
Changed

igraph_eigenvector_centrality()
assumes the adjacency matrix of undirected graphs to have twice the number of selfloops for each vertex on the diagonal. This makes the results consistent between an undirected graph and its directed equivalent when each edge is replaced by a mutual edge pair.
Fixed

igraph_isomorphic()
now verifies that the input graphs have no multiedges (PR #1464). 
igraph_difference()
was creating superfluous self loops (#597). 
igraph_count_multiple()
was giving incorrect results for selfloops in directed graph (PR #1399). 
igraph_betweenness_estimate()
: fixed incorrect results with finite cutoff (PR #1392). 
igraph_eigen_matrix_symmetric()
: fixed incorrect matrix multiplication (PR #1379).  Corrected several issues that could arise during an error condition (PRs #1405, #1406, #1438).

igraph_realize_degree_sequence()
did not correctly detect some nongraphical inputs. 
igraph_is_graphical_degree_sequence()
: fixed incorrect results in undirected case (PR #1441). 
igraph_community_leiden()
: fixed incorrect result when selfloops are present (PR #1476). 
igraph_eigenvector_centrality()
: fixed incorrect value for isolated vertices in weighted graphs. 
igraph_eigenvector_centrality()
: corrected the handling of selfloops. 
igraph_layout_reingold_tilford()
: fixed an issue where branches of the tree would sometimes overlap.
Other

igraph_degree_sequence_game()
: improved performance withIGRAPH_DEGSEQ_SIMPLE_NO_MULTIPLE_UNIFORM
method.  Improved the robustness of the test suite.
 Documentation improvements.
 Improved error and warning messages.
 Improved compatibility with recent versions of Microsoft Visual C.