Roger Elwell, VP of Strate­gic Part­ners and Alliance at SNP Group, wrote this ASUG Mem­ber blog post.

Since SAP announced the end of sup­port for SAP Busi­ness Suite 7 effec­tive 2027, the need for an SAP S/4HANA migra­tion has tak­en on renewed urgency. Already, busi­ness­es world­wide are in var­i­ous stages of their own SAP S/4HANA jour­neys, rang­ing from actu­al imple­men­ta­tion to devel­op­ing proofs of con­cept to still sketch­ing out the ini­tial planning. 

But what’s true for every one of these orga­ni­za­tions is that no two migra­tions will look the same. Every company’s path to SAP S/4HANA is unique and thus requires an approach tai­lored to its own needs and environments.

While there is no one-size-fits-all strat­e­gy for SAP S/4HANA migra­tion, no mat­ter the approach, cer­tain box­es must be ticked.

• Is it cost-effective? 
• Does it involve min­i­mal risk? 
• Does it effi­cient­ly and secure­ly migrate the nec­es­sary sys­tems and data sets? 
• How will it impact longer-term strate­gic plan­ning around dig­i­tal transformation? 

SAP S/4HANA has a major role to play in mod­ern­iz­ing an organization’s busi­ness sys­tems and process­es, so find­ing a method­ol­o­gy that address­es these con­cerns is critical. 

As a result, busi­ness­es tend to coa­lesce around one of three gen­er­al migra­tion approach­es: brown­field, green­field, and blue­field. Each path has its pros and cons, and I’ll break those down below, as well as how enter­pris­es might be able to nav­i­gate an approach that gets ​“the best of both worlds” while migrat­ing to SAP S/4HANA.

Brown­field Approach: An Across-the-Board Update 

The brown­field approach aims to trans­form exist­ing sys­tems. It’s a tech­ni­cal upgrade that will update your exist­ing soft­ware on the books, com­pre­hen­sive­ly but indis­crim­i­nate­ly mov­ing data sets, cus­tomiza­tions, and oth­er objects to the new plat­form. Often, more recent SAP adopters (i.e., busi­ness­es that have moved to SAP with­in the past five years or so) will choose to go the brown­field route. 

The appeal of brown­field is in its sim­plic­i­ty: it moves the entire exist­ing SAP ECC sys­tem to SAP S/4HANA. It’s a thor­ough and sim­ple lift and shift that pre­serves the struc­ture you already have in place. It doesn’t rock the boat and is easy enough to execute.

That sim­plic­i­ty is also its down­side, though. Brown­field doesn’t offer a selec­tive approach, where you can choose what to upgrade and migrate. Instead, every­thing about your cur­rent sys­tem gets car­ried over. That means old busi­ness process­es or unused com­po­nents that should be retired are still preserved. 

What could’ve been an oppor­tu­ni­ty to reassess — exam­ine tech­ni­cal debt, elim­i­nate the process­es and sys­tems you don’t need, and only pre­serve those you do — is trad­ed for a straight­for­ward, across-the-board migra­tion. It effec­tive­ly leaves you stuck in place with the sys­tems you have rather than tak­ing advan­tage of the new fea­tures and inno­va­tions that SAP S/4HANA brings to the table. 

Green­field Approach: Imple­men­ta­tion From the Ground Up

While brown­field lifts and shifts your exist­ing sys­tems, the green­field approach takes the oppo­site tack and starts from scratch with a com­plete­ly new imple­men­ta­tion. Green­field is a fun­da­men­tal change, in both func­tion and tech­ni­cal details, from your cur­rent SAP imple­men­ta­tion, cre­at­ing an entire­ly new sys­tem with new busi­ness process­es and con­fig­u­ra­tions. By essen­tial­ly wip­ing the slate clean, green­field pro­vides busi­ness­es with a new oppor­tu­ni­ty to con­sol­i­date dis­parate ERP sys­tems into a cohe­sive plat­form, built from the ground up, with brand-new and sig­nif­i­cant­ly upgrad­ed busi­ness process­es and configurations. 

So, what’s the catch? If brown­field is too reliant on exist­ing sys­tems and process­es, then green­field is over­ly dis­mis­sive of them. It’s one thing if your envi­ron­ment con­tains a lot of cus­tom code that you’d pre­fer to replace with the most up-to-date SAP log­ic. But if there is his­tor­i­cal data or con­fig­u­ra­tions you pre­fer to use — and maybe more impor­tant­ly, his­tor­i­cal data that you must pre­serve for reg­u­la­to­ry rea­sons — then green­field won’t car­ry it over. 

Like brown­field, green­field offers no oppor­tu­ni­ty for selec­tive­ness. Both approach­es are ​“all or noth­ing,” leav­ing no room to choose what to migrate and upgrade. As a result, both green­field and brown­field lim­it the final state of your SAP S/4HANA platform.

Blue­field Approach: Pick and Choose What You Want to Migrate

A ​“blue­field” migra­tion — between green­field and brown­field — is ide­al for large com­pa­nies with very com­plex IT envi­ron­ments. Unlike brown­field and green­field, which han­dle SAP S/4HANA migra­tion with a broad brush — either upgrad­ing every­thing or scrap­ping every­thing and build­ing a new imple­men­ta­tion from scratch — blue­field allows busi­ness­es to be more selec­tive in their migrations. 

Selec­tive migra­tions give enter­pris­es a choice in which data and con­fig­u­ra­tions to car­ry over. That lev­el of flex­i­bil­i­ty allows busi­ness­es to reassess the data, busi­ness process­es, and cus­tomiza­tions they’ve accu­mu­lat­ed in the back­ground for years. Want to restruc­ture and dig­i­tal­ly trans­form your sys­tems to bet­ter cap­i­tal­ize on the fea­tures of SAP S/4HANA? Or ditch old process­es and con­fig­u­ra­tions that are nei­ther effi­cient nor use­ful but have got­ten by thanks to being ​“out of sight, out of mind?” Tak­ing the selec­tive migra­tion path offers an oppor­tu­ni­ty to tack­le these items finally. 

This selec­tive­ness can also be a boon for busi­ness­es in indus­tries that must com­ply with cer­tain his­tor­i­cal data reg­u­la­to­ry stan­dards. The abil­i­ty to selec­tive­ly choose which data to migrate and which to aban­don ensures that your SAP S/4HANA migra­tion method won’t inad­ver­tent­ly lose nec­es­sary his­tor­i­cal data and poten­tial­ly put you at risk of non-compliance. 

Of course, the val­ue of this selec­tive­ness depends on your will­ing­ness and inter­est in pick­ing and choos­ing par­tic­u­lar data sets or con­fig­u­ra­tions to migrate or leave behind. Oth­er­wise, the all-or-noth­ing green­field or brown­field migra­tion approach may be a more appeal­ing pathway.

Depend­ing on your organization’s needs — like the size and com­plex­i­ty of your SAP plat­form and the need (or not) to pre­serve cer­tain his­tor­i­cal data sets and con­fig­u­ra­tions ver­sus the desire to start fresh — a brown­field or green­field approach may serve you just fine. But luck­i­ly, there’s a ​“best-of-both-worlds” approach avail­able to com­pa­nies look­ing for total selec­tive con­trol over their busi­ness-crit­i­cal data and con­fig­u­ra­tion migra­tions and per­form­ing them with­in a sin­gle go-live project. 

Need more help fig­ur­ing out your SAP S/4HANA migra­tion? Fol­low the ASUG SAP S/4HANA(ERP) Com­mu­ni­ty Alliance or join the SAP S/4HANA Migra­tion Influ­ence Coun­cil.