Preparation for the release of TeX Live 2016 have started some time ago with the freeze of updates in TeX Live 2015. Yesterday we announced the official start of the pretest period. That means that we invite people to test the new release and help fixing bugs. At the same time I have uploaded the first set of packages of TeX Live 2016 for Debian to the experimental suite.
Concerning the binaries we do expect a few further changes, but hopefully nothing drastic. The most invasive change on the tlmgr side is that cryptographic signatures are now verified to guarantee authenticity of the packages downloaded, but this is rather irrelevant for Debian users (though I will look into how that works in user mode).
Other than that, many packages have been updated or added since the last Debian packages, here is the unified list:
acro, animate, appendixnumberbeamer, arabluatex, asapsym, asciilist, babel-belarusian, bibarts, biblatex-bookinarticle, biblatex-bookinother, biblatex-caspervector, biblatex-chicago, biblatex-gost, biblatex-ieee, biblatex-morenames, biblatex-opcit-booktitle, bibtexperllibs, bxdvidriver, bxenclose, bxjscls, bxnewfont, bxpapersize, chemnum, cjk-ko, cochineal, csplain, cstex, datetime2-finnish, denisbdoc, dtx, dvipdfmx-def, ejpecp, emisa, fithesis, fnpct, font-change-xetex, forest, formation-latex-ul, gregoriotex, gzt, hausarbeit-jura, hyperxmp, imakeidx, jacow, l3, l3kernel, l3packages, latex2e, latex2e-help-texinfo-fr, latex-bib2-ex, libertinust1math, lollipop, lt3graph, lua-check-hyphen, lualibs, luamplib, luatexja, mathalfa, mathastext, mcf2graph, media9, metrix, nameauth, ndsu-thesis, newtx, normalcolor, noto, nucleardata, nwejm, ocgx2, pdfcomment, pdfpages, pkuthss, polyglossia, proposal, qcircuit, reledmac, rmathbr, savetrees, scanpages, stex, suftesi, svrsymbols, teubner, tex4ebook, tex-ini-files, tikzmark, tikzsymbols, titlesec, tudscr, typed-checklist, ulthese, visualtikz, xespotcolor, xetex-def, xetexko, ycbook, yinit-otf.